Update nlopes/slack to 4.1-dev (#595)

34 files changed, 647 insertions, 497 deletions

diff --git a/vendor/github.com/nlopes/slack/.travis.yml b/vendor/github.com/nlopes/slack/.travis.yml
index bd0539e0..b0615288 100644
--- a/vendor/github.com/nlopes/slack/.travis.yml
+++ b/vendor/github.com/nlopes/slack/.travis.yml
@@ -4,6 +4,8 @@ go:
     - 1.7.x
     - 1.8.x
     - 1.9.x
+    - 1.10.x
+    - 1.11.x
     - tip
 
 before_install:
diff --git a/vendor/github.com/nlopes/slack/admin.go b/vendor/github.com/nlopes/slack/admin.go
index a2aa7e5c..db44aa38 100644
--- a/vendor/github.com/nlopes/slack/admin.go
+++ b/vendor/github.com/nlopes/slack/admin.go
@@ -12,9 +12,9 @@ type adminResponse struct {
 	Error string `json:"error"`
 }
 
-func adminRequest(ctx context.Context, client HTTPRequester, method string, teamName string, values url.Values, debug bool) (*adminResponse, error) {
+func adminRequest(ctx context.Context, client httpClient, method string, teamName string, values url.Values, d debug) (*adminResponse, error) {
 	adminResponse := &adminResponse{}
-	err := parseAdminResponse(ctx, client, method, teamName, values, adminResponse, debug)
+	err := parseAdminResponse(ctx, client, method, teamName, values, adminResponse, d)
 	if err != nil {
 		return nil, err
 	}
@@ -40,7 +40,7 @@ func (api *Client) DisableUserContext(ctx context.Context, teamName string, uid
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "setInactive", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "setInactive", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to disable user with id '%s': %s", uid, err)
 	}
@@ -67,7 +67,7 @@ func (api *Client) InviteGuestContext(ctx context.Context, teamName, channel, fi
 		"_attempts":        {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "invite", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "invite", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to invite single-channel guest: %s", err)
 	}
@@ -94,7 +94,7 @@ func (api *Client) InviteRestrictedContext(ctx context.Context, teamName, channe
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "invite", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "invite", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to restricted account: %s", err)
 	}
@@ -118,7 +118,7 @@ func (api *Client) InviteToTeamContext(ctx context.Context, teamName, firstName,
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "invite", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "invite", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to invite to team: %s", err)
 	}
@@ -140,7 +140,7 @@ func (api *Client) SetRegularContext(ctx context.Context, teamName, user string)
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "setRegular", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "setRegular", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to change the user (%s) to a regular user: %s", user, err)
 	}
@@ -162,7 +162,7 @@ func (api *Client) SendSSOBindingEmailContext(ctx context.Context, teamName, use
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "sendSSOBind", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "sendSSOBind", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to send SSO binding email for user (%s): %s", user, err)
 	}
@@ -185,7 +185,7 @@ func (api *Client) SetUltraRestrictedContext(ctx context.Context, teamName, uid,
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "setUltraRestricted", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "setUltraRestricted", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to ultra-restrict account: %s", err)
 	}
@@ -207,7 +207,7 @@ func (api *Client) SetRestrictedContext(ctx context.Context, teamName, uid strin
 		"_attempts":  {"1"},
 	}
 
-	_, err := adminRequest(ctx, api.httpclient, "setRestricted", teamName, values, api.debug)
+	_, err := adminRequest(ctx, api.httpclient, "setRestricted", teamName, values, api)
 	if err != nil {
 		return fmt.Errorf("Failed to restrict account: %s", err)
 	}
diff --git a/vendor/github.com/nlopes/slack/attachments.go b/vendor/github.com/nlopes/slack/attachments.go
index 326fc010..06f59fa3 100644
--- a/vendor/github.com/nlopes/slack/attachments.go
+++ b/vendor/github.com/nlopes/slack/attachments.go
@@ -42,24 +42,14 @@ type AttachmentActionOptionGroup struct {
 }
 
 // AttachmentActionCallback is sent from Slack when a user clicks a button in an interactive message (aka AttachmentAction)
-type AttachmentActionCallback struct {
-	Actions    []AttachmentAction `json:"actions"`
-	CallbackID string             `json:"callback_id"`
-	Team       Team               `json:"team"`
-	Channel    Channel            `json:"channel"`
-	User       User               `json:"user"`
-
-	Name  string `json:"name"`
-	Value string `json:"value"`
-
-	OriginalMessage Message `json:"original_message"`
-
-	ActionTs     string `json:"action_ts"`
-	MessageTs    string `json:"message_ts"`
-	AttachmentID string `json:"attachment_id"`
-	Token        string `json:"token"`
-	ResponseURL  string `json:"response_url"`
-	TriggerID    string `json:"trigger_id"`
+// DEPRECATED: use InteractionCallback
+type AttachmentActionCallback InteractionCallback
+
+// ActionCallback specific fields for the action callback.
+type ActionCallback struct {
+	MessageTs    string             `json:"message_ts"`
+	AttachmentID string             `json:"attachment_id"`
+	Actions      []AttachmentAction `json:"actions"`
 }
 
 // ConfirmationField are used to ask users to confirm actions
diff --git a/vendor/github.com/nlopes/slack/auth.go b/vendor/github.com/nlopes/slack/auth.go
new file mode 100644
index 00000000..f8fe1f9d
--- /dev/null
+++ b/vendor/github.com/nlopes/slack/auth.go
@@ -0,0 +1,40 @@
+package slack
+
+import (
+	"context"
+	"net/url"
+)
+
+// AuthRevokeResponse contains our Auth response from the auth.revoke endpoint
+type AuthRevokeResponse struct {
+	SlackResponse      // Contains the "ok", and "Error", if any
+	Revoked       bool `json:"revoked,omitempty"`
+}
+
+// authRequest sends the actual request, and unmarshals the response
+func authRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*AuthRevokeResponse, error) {
+	response := &AuthRevokeResponse{}
+	err := postSlackMethod(ctx, client, path, values, response, d)
+	if err != nil {
+		return nil, err
+	}
+
+	return response, response.Err()
+}
+
+// SendAuthRevoke will send a revocation for our token
+func (api *Client) SendAuthRevoke(token string) (*AuthRevokeResponse, error) {
+	return api.SendAuthRevokeContext(context.Background(), token)
+}
+
+// SendAuthRevokeContext will retrieve the satus from api.test
+func (api *Client) SendAuthRevokeContext(ctx context.Context, token string) (*AuthRevokeResponse, error) {
+	if token == "" {
+		token = api.token
+	}
+	values := url.Values{
+		"token": {token},
+	}
+
+	return authRequest(ctx, api.httpclient, "auth.revoke", values, api)
+}
diff --git a/vendor/github.com/nlopes/slack/bots.go b/vendor/github.com/nlopes/slack/bots.go
index 92570a04..e27e76ab 100644
--- a/vendor/github.com/nlopes/slack/bots.go
+++ b/vendor/github.com/nlopes/slack/bots.go
@@ -19,9 +19,9 @@ type botResponseFull struct {
 	SlackResponse
 }
 
-func botRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*botResponseFull, error) {
+func botRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*botResponseFull, error) {
 	response := &botResponseFull{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
@@ -43,7 +43,7 @@ func (api *Client) GetBotInfoContext(ctx context.Context, bot string) (*Bot, err
 		"bot":   {bot},
 	}
 
-	response, err := botRequest(ctx, api.httpclient, "bots.info", values, api.debug)
+	response, err := botRequest(ctx, api.httpclient, "bots.info", values, api)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/channels.go b/vendor/github.com/nlopes/slack/channels.go
index 6204315a..007985bc 100644
--- a/vendor/github.com/nlopes/slack/channels.go
+++ b/vendor/github.com/nlopes/slack/channels.go
@@ -26,9 +26,9 @@ type Channel struct {
 	Locale    string `json:"locale"`
 }
 
-func channelRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*channelResponseFull, error) {
+func channelRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*channelResponseFull, error) {
 	response := &channelResponseFull{}
-	err := postForm(ctx, client, SLACK_API+path, values, response, debug)
+	err := postForm(ctx, client, APIURL+path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
@@ -52,7 +52,7 @@ func (api *Client) ArchiveChannelContext(ctx context.Context, channelID string)
 		"channel": {channelID},
 	}
 
-	_, err = channelRequest(ctx, api.httpclient, "channels.archive", values, api.debug)
+	_, err = channelRequest(ctx, api.httpclient, "channels.archive", values, api)
 	return err
 }
 
@@ -70,7 +70,7 @@ func (api *Client) UnarchiveChannelContext(ctx context.Context, channelID string
 		"channel": {channelID},
 	}
 
-	_, err = channelRequest(ctx, api.httpclient, "channels.unarchive", values, api.debug)
+	_, err = channelRequest(ctx, api.httpclient, "channels.unarchive", values, api)
 	return err
 }
 
@@ -88,7 +88,7 @@ func (api *Client) CreateChannelContext(ctx context.Context, channelName string)
 		"name":  {channelName},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.create", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.create", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -133,7 +133,7 @@ func (api *Client) GetChannelHistoryContext(ctx context.Context, channelID strin
 		}
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.history", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.history", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -154,7 +154,7 @@ func (api *Client) GetChannelInfoContext(ctx context.Context, channelID string)
 		"channel": {channelID},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.info", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.info", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -167,7 +167,7 @@ func (api *Client) InviteUserToChannel(channelID, user string) (*Channel, error)
 	return api.InviteUserToChannelContext(context.Background(), channelID, user)
 }
 
-// InviteUserToChannelCustom invites a user to a given channel and returns a *Channel with a custom context
+// InviteUserToChannelContext invites a user to a given channel and returns a *Channel with a custom context
 // see https://api.slack.com/methods/channels.invite
 func (api *Client) InviteUserToChannelContext(ctx context.Context, channelID, user string) (*Channel, error) {
 	values := url.Values{
@@ -176,7 +176,7 @@ func (api *Client) InviteUserToChannelContext(ctx context.Context, channelID, us
 		"user":    {user},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.invite", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.invite", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -197,7 +197,7 @@ func (api *Client) JoinChannelContext(ctx context.Context, channelName string) (
 		"name":  {channelName},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.join", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.join", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -218,7 +218,7 @@ func (api *Client) LeaveChannelContext(ctx context.Context, channelID string) (b
 		"channel": {channelID},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.leave", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.leave", values, api)
 	if err != nil {
 		return false, err
 	}
@@ -241,7 +241,7 @@ func (api *Client) KickUserFromChannelContext(ctx context.Context, channelID, us
 		"user":    {user},
 	}
 
-	_, err = channelRequest(ctx, api.httpclient, "channels.kick", values, api.debug)
+	_, err = channelRequest(ctx, api.httpclient, "channels.kick", values, api)
 	return err
 }
 
@@ -261,7 +261,7 @@ func (api *Client) GetChannelsContext(ctx context.Context, excludeArchived bool)
 		values.Add("exclude_archived", "1")
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.list", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.list", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -288,7 +288,7 @@ func (api *Client) SetChannelReadMarkContext(ctx context.Context, channelID, ts
 		"ts":      {ts},
 	}
 
-	_, err = channelRequest(ctx, api.httpclient, "channels.mark", values, api.debug)
+	_, err = channelRequest(ctx, api.httpclient, "channels.mark", values, api)
 	return err
 }
 
@@ -309,7 +309,7 @@ func (api *Client) RenameChannelContext(ctx context.Context, channelID, name str
 
 	// XXX: the created entry in this call returns a string instead of a number
 	// so I may have to do some workaround to solve it.
-	response, err := channelRequest(ctx, api.httpclient, "channels.rename", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.rename", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -331,7 +331,7 @@ func (api *Client) SetChannelPurposeContext(ctx context.Context, channelID, purp
 		"purpose": {purpose},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.setPurpose", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.setPurpose", values, api)
 	if err != nil {
 		return "", err
 	}
@@ -353,7 +353,7 @@ func (api *Client) SetChannelTopicContext(ctx context.Context, channelID, topic
 		"topic":   {topic},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "channels.setTopic", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.setTopic", values, api)
 	if err != nil {
 		return "", err
 	}
@@ -374,7 +374,7 @@ func (api *Client) GetChannelRepliesContext(ctx context.Context, channelID, thre
 		"channel":   {channelID},
 		"thread_ts": {thread_ts},
 	}
-	response, err := channelRequest(ctx, api.httpclient, "channels.replies", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "channels.replies", values, api)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/chat.go b/vendor/github.com/nlopes/slack/chat.go
index 8cc6bdef..eb8fd6c8 100644
--- a/vendor/github.com/nlopes/slack/chat.go
+++ b/vendor/github.com/nlopes/slack/chat.go
@@ -96,26 +96,24 @@ func (api *Client) DeleteMessageContext(ctx context.Context, channel, messageTim
 // PostMessage sends a message to a channel.
 // Message is escaped by default according to https://api.slack.com/docs/formatting
 // Use http://davestevens.github.io/slack-message-builder/ to help crafting your message.
-func (api *Client) PostMessage(channel, text string, params PostMessageParameters) (string, string, error) {
+func (api *Client) PostMessage(channelID string, options ...MsgOption) (string, string, error) {
 	respChannel, respTimestamp, _, err := api.SendMessageContext(
 		context.Background(),
-		channel,
-		MsgOptionText(text, params.EscapeText),
-		MsgOptionAttachments(params.Attachments...),
-		MsgOptionPostMessageParameters(params),
+		channelID,
+		MsgOptionPost(),
+		MsgOptionCompose(options...),
 	)
 	return respChannel, respTimestamp, err
 }
 
 // PostMessageContext sends a message to a channel with a custom context
-// For more details, see PostMessage documentation
-func (api *Client) PostMessageContext(ctx context.Context, channel, text string, params PostMessageParameters) (string, string, error) {
+// For more details, see PostMessage documentation.
+func (api *Client) PostMessageContext(ctx context.Context, channelID string, options ...MsgOption) (string, string, error) {
 	respChannel, respTimestamp, _, err := api.SendMessageContext(
 		ctx,
-		channel,
-		MsgOptionText(text, params.EscapeText),
-		MsgOptionAttachments(params.Attachments...),
-		MsgOptionPostMessageParameters(params),
+		channelID,
+		MsgOptionPost(),
+		MsgOptionCompose(options...),
 	)
 	return respChannel, respTimestamp, err
 }
@@ -135,18 +133,23 @@ func (api *Client) PostEphemeral(channelID, userID string, options ...MsgOption)
 // PostEphemeralContext sends an ephemeal message to a user in a channel with a custom context
 // For more details, see PostEphemeral documentation
 func (api *Client) PostEphemeralContext(ctx context.Context, channelID, userID string, options ...MsgOption) (timestamp string, err error) {
-	_, timestamp, _, err = api.SendMessageContext(ctx, channelID, append(options, MsgOptionPostEphemeral2(userID))...)
+	_, timestamp, _, err = api.SendMessageContext(ctx, channelID, MsgOptionPostEphemeral(userID), MsgOptionCompose(options...))
 	return timestamp, err
 }
 
 // UpdateMessage updates a message in a channel
-func (api *Client) UpdateMessage(channelID, timestamp, text string) (string, string, string, error) {
-	return api.UpdateMessageContext(context.Background(), channelID, timestamp, text)
+func (api *Client) UpdateMessage(channelID, timestamp string, options ...MsgOption) (string, string, string, error) {
+	return api.SendMessageContext(context.Background(), channelID, MsgOptionUpdate(timestamp), MsgOptionCompose(options...))
 }
 
 // UpdateMessageContext updates a message in a channel
-func (api *Client) UpdateMessageContext(ctx context.Context, channelID, timestamp, text string) (string, string, string, error) {
-	return api.SendMessageContext(ctx, channelID, MsgOptionUpdate(timestamp), MsgOptionText(text, true))
+func (api *Client) UpdateMessageContext(ctx context.Context, channelID, timestamp string, options ...MsgOption) (string, string, string, error) {
+	return api.SendMessageContext(ctx, channelID, MsgOptionUpdate(timestamp), MsgOptionCompose(options...))
+}
+
+// UnfurlMessage unfurls a message in a channel
+func (api *Client) UnfurlMessage(channelID, timestamp string, unfurls map[string]Attachment, options ...MsgOption) (string, string, string, error) {
+	return api.SendMessageContext(context.Background(), channelID, MsgOptionUnfurl(timestamp, unfurls), MsgOptionCompose(options...))
 }
 
 // SendMessage more flexible method for configuring messages.
@@ -165,7 +168,7 @@ func (api *Client) SendMessageContext(ctx context.Context, channelID string, opt
 		return "", "", "", err
 	}
 
-	if err = postForm(ctx, api.httpclient, config.endpoint, config.values, &response, api.debug); err != nil {
+	if err = postForm(ctx, api.httpclient, config.endpoint, config.values, &response, api); err != nil {
 		return "", "", "", err
 	}
 
@@ -182,7 +185,7 @@ func UnsafeApplyMsgOptions(token, channel string, options ...MsgOption) (string,
 
 func applyMsgOptions(token, channel string, options ...MsgOption) (sendConfig, error) {
 	config := sendConfig{
-		endpoint: SLACK_API + string(chatPostMessage),
+		endpoint: APIURL + string(chatPostMessage),
 		values: url.Values{
 			"token":   {token},
 			"channel": {channel},
@@ -206,6 +209,7 @@ const (
 	chatDelete        sendMode = "chat.delete"
 	chatPostEphemeral sendMode = "chat.postEphemeral"
 	chatMeMessage     sendMode = "chat.meMessage"
+	chatUnfurl        sendMode = "chat.unfurl"
 )
 
 type sendConfig struct {
@@ -219,26 +223,16 @@ type MsgOption func(*sendConfig) error
 // MsgOptionPost posts a messages, this is the default.
 func MsgOptionPost() MsgOption {
 	return func(config *sendConfig) error {
-		config.endpoint = SLACK_API + string(chatPostMessage)
-		config.values.Del("ts")
-		return nil
-	}
-}
-
-// MsgOptionPostEphemeral - DEPRECATED: use MsgOptionPostEphemeral2
-// posts an ephemeral message.
-func MsgOptionPostEphemeral() MsgOption {
-	return func(config *sendConfig) error {
-		config.endpoint = SLACK_API + string(chatPostEphemeral)
+		config.endpoint = APIURL + string(chatPostMessage)
 		config.values.Del("ts")
 		return nil
 	}
 }
 
-// MsgOptionPostEphemeral2 - posts an ephemeral message to the provided user.
-func MsgOptionPostEphemeral2(userID string) MsgOption {
+// MsgOptionPostEphemeral - posts an ephemeral message to the provided user.
+func MsgOptionPostEphemeral(userID string) MsgOption {
 	return func(config *sendConfig) error {
-		config.endpoint = SLACK_API + string(chatPostEphemeral)
+		config.endpoint = APIURL + string(chatPostEphemeral)
 		MsgOptionUser(userID)(config)
 		config.values.Del("ts")
 
@@ -249,7 +243,7 @@ func MsgOptionPostEphemeral2(userID string) MsgOption {
 // MsgOptionMeMessage posts a "me message" type from the calling user
 func MsgOptionMeMessage() MsgOption {
 	return func(config *sendConfig) error {
-		config.endpoint = SLACK_API + string(chatMeMessage)
+		config.endpoint = APIURL + string(chatMeMessage)
 		return nil
 	}
 }
@@ -257,7 +251,7 @@ func MsgOptionMeMessage() MsgOption {
 // MsgOptionUpdate updates a message based on the timestamp.
 func MsgOptionUpdate(timestamp string) MsgOption {
 	return func(config *sendConfig) error {
-		config.endpoint = SLACK_API + string(chatUpdate)
+		config.endpoint = APIURL + string(chatUpdate)
 		config.values.Add("ts", timestamp)
 		return nil
 	}
@@ -266,12 +260,25 @@ func MsgOptionUpdate(timestamp string) MsgOption {
 // MsgOptionDelete deletes a message based on the timestamp.
 func MsgOptionDelete(timestamp string) MsgOption {
 	return func(config *sendConfig) error {
-		config.endpoint = SLACK_API + string(chatDelete)
+		config.endpoint = APIURL + string(chatDelete)
 		config.values.Add("ts", timestamp)
 		return nil
 	}
 }
 
+// MsgOptionUnfurl unfurls a message based on the timestamp.
+func MsgOptionUnfurl(timestamp string, unfurls map[string]Attachment) MsgOption {
+	return func(config *sendConfig) error {
+		config.endpoint = APIURL + string(chatUnfurl)
+		config.values.Add("ts", timestamp)
+		unfurlsStr, err := json.Marshal(unfurls)
+		if err == nil {
+			config.values.Add("unfurls", string(unfurlsStr))
+		}
+		return err
+	}
+}
+
 // MsgOptionAsUser whether or not to send the message as the user.
 func MsgOptionAsUser(b bool) MsgOption {
 	return func(config *sendConfig) error {
@@ -290,6 +297,14 @@ func MsgOptionUser(userID string) MsgOption {
 	}
 }
 
+// MsgOptionUsername set the username for the message.
+func MsgOptionUsername(username string) MsgOption {
+	return func(config *sendConfig) error {
+		config.values.Set("username", username)
+		return nil
+	}
+}
+
 // MsgOptionText provide the text for the message, optionally escape the provided
 // text.
 func MsgOptionText(text string, escape bool) MsgOption {
@@ -365,7 +380,7 @@ func MsgOptionBroadcast() MsgOption {
 	}
 }
 
-// this function combines multiple options into a single option.
+// MsgOptionCompose combines multiple options into a single option.
 func MsgOptionCompose(options ...MsgOption) MsgOption {
 	return func(c *sendConfig) error {
 		for _, opt := range options {
@@ -377,6 +392,7 @@ func MsgOptionCompose(options ...MsgOption) MsgOption {
 	}
 }
 
+// MsgOptionParse set parse option.
 func MsgOptionParse(b bool) MsgOption {
 	return func(c *sendConfig) error {
 		var v string
@@ -456,3 +472,38 @@ func MsgOptionPostMessageParameters(params PostMessageParameters) MsgOption {
 		return nil
 	}
 }
+
+// PermalinkParameters are the parameters required to get a permalink to a
+// message. Slack documentation can be found here:
+// https://api.slack.com/methods/chat.getPermalink
+type PermalinkParameters struct {
+	Channel string
+	Ts      string
+}
+
+// GetPermalink returns the permalink for a message. It takes
+// PermalinkParameters and returns a string containing the permalink. It
+// returns an error if unable to retrieve the permalink.
+func (api *Client) GetPermalink(params *PermalinkParameters) (string, error) {
+	return api.GetPermalinkContext(context.Background(), params)
+}
+
+// GetPermalinkContext returns the permalink for a message using a custom context.
+func (api *Client) GetPermalinkContext(ctx context.Context, params *PermalinkParameters) (string, error) {
+	values := url.Values{
+		"token":      {api.token},
+		"channel":    {params.Channel},
+		"message_ts": {params.Ts},
+	}
+
+	response := struct {
+		Channel   string `json:"channel"`
+		Permalink string `json:"permalink"`
+		SlackResponse
+	}{}
+	err := getSlackMethod(ctx, api.httpclient, "chat.getPermalink", values, &response, api)
+	if err != nil {
+		return "", err
+	}
+	return response.Permalink, response.Err()
+}
diff --git a/vendor/github.com/nlopes/slack/conversation.go b/vendor/github.com/nlopes/slack/conversation.go
index 1c64116e..ccd38f88 100644
--- a/vendor/github.com/nlopes/slack/conversation.go
+++ b/vendor/github.com/nlopes/slack/conversation.go
@@ -99,7 +99,7 @@ func (api *Client) GetUsersInConversationContext(ctx context.Context, params *Ge
 		ResponseMetaData responseMetaData `json:"response_metadata"`
 		SlackResponse
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.members", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.members", values, &response, api)
 	if err != nil {
 		return nil, "", err
 	}
@@ -118,7 +118,9 @@ func (api *Client) GetConversationsForUser(params *GetConversationsForUserParame
 func (api *Client) GetConversationsForUserContext(ctx context.Context, params *GetConversationsForUserParameters) (channels []Channel, nextCursor string, err error) {
 	values := url.Values{
 		"token": {api.token},
-		"user":  {params.UserID},
+	}
+	if params.UserID != "" {
+		values.Add("user", params.UserID)
 	}
 	if params.Cursor != "" {
 		values.Add("cursor", params.Cursor)
@@ -134,14 +136,12 @@ func (api *Client) GetConversationsForUserContext(ctx context.Context, params *G
 		ResponseMetaData responseMetaData `json:"response_metadata"`
 		SlackResponse
 	}{}
-	err = postSlackMethod(ctx, api.httpclient, "users.conversations", values, &response, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "users.conversations", values, &response, api)
 	if err != nil {
 		return nil, "", err
 	}
-	if !response.Ok {
-		return nil, "", errors.New(response.Error)
-	}
-	return response.Channels, response.ResponseMetaData.NextCursor, nil
+
+	return response.Channels, response.ResponseMetaData.NextCursor, response.Err()
 }
 
 // ArchiveConversation archives a conversation
@@ -156,7 +156,7 @@ func (api *Client) ArchiveConversationContext(ctx context.Context, channelID str
 		"channel": {channelID},
 	}
 	response := SlackResponse{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.archive", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.archive", values, &response, api)
 	if err != nil {
 		return err
 	}
@@ -176,7 +176,7 @@ func (api *Client) UnArchiveConversationContext(ctx context.Context, channelID s
 		"channel": {channelID},
 	}
 	response := SlackResponse{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.unarchive", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.unarchive", values, &response, api)
 	if err != nil {
 		return err
 	}
@@ -200,7 +200,7 @@ func (api *Client) SetTopicOfConversationContext(ctx context.Context, channelID,
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.setTopic", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.setTopic", values, &response, api)
 	if err != nil {
 		return nil, err
 	}
@@ -224,7 +224,7 @@ func (api *Client) SetPurposeOfConversationContext(ctx context.Context, channelI
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.setPurpose", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.setPurpose", values, &response, api)
 	if err != nil {
 		return nil, err
 	}
@@ -248,7 +248,7 @@ func (api *Client) RenameConversationContext(ctx context.Context, channelID, cha
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.rename", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.rename", values, &response, api)
 	if err != nil {
 		return nil, err
 	}
@@ -272,7 +272,7 @@ func (api *Client) InviteUsersToConversationContext(ctx context.Context, channel
 		SlackResponse
 		Channel *Channel `json:"channel"`
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.invite", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.invite", values, &response, api)
 	if err != nil {
 		return nil, err
 	}
@@ -293,7 +293,7 @@ func (api *Client) KickUserFromConversationContext(ctx context.Context, channelI
 		"user":    {user},
 	}
 	response := SlackResponse{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.kick", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.kick", values, &response, api)
 	if err != nil {
 		return err
 	}
@@ -318,7 +318,7 @@ func (api *Client) CloseConversationContext(ctx context.Context, channelID strin
 		AlreadyClosed bool `json:"already_closed"`
 	}{}
 
-	err = postSlackMethod(ctx, api.httpclient, "conversations.close", values, &response, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "conversations.close", values, &response, api)
 	if err != nil {
 		return false, false, err
 	}
@@ -339,7 +339,7 @@ func (api *Client) CreateConversationContext(ctx context.Context, channelName st
 		"is_private": {strconv.FormatBool(isPrivate)},
 	}
 	response, err := channelRequest(
-		ctx, api.httpclient, "conversations.create", values, api.debug)
+		ctx, api.httpclient, "conversations.create", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -360,7 +360,7 @@ func (api *Client) GetConversationInfoContext(ctx context.Context, channelID str
 		"include_locale": {strconv.FormatBool(includeLocale)},
 	}
 	response, err := channelRequest(
-		ctx, api.httpclient, "conversations.info", values, api.debug)
+		ctx, api.httpclient, "conversations.info", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -380,7 +380,7 @@ func (api *Client) LeaveConversationContext(ctx context.Context, channelID strin
 		"channel": {channelID},
 	}
 
-	response, err := channelRequest(ctx, api.httpclient, "conversations.leave", values, api.debug)
+	response, err := channelRequest(ctx, api.httpclient, "conversations.leave", values, api)
 	if err != nil {
 		return false, err
 	}
@@ -436,7 +436,7 @@ func (api *Client) GetConversationRepliesContext(ctx context.Context, params *Ge
 		Messages []Message `json:"messages"`
 	}{}
 
-	err = postSlackMethod(ctx, api.httpclient, "conversations.replies", values, &response, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "conversations.replies", values, &response, api)
 	if err != nil {
 		return nil, false, "", err
 	}
@@ -476,7 +476,7 @@ func (api *Client) GetConversationsContext(ctx context.Context, params *GetConve
 		ResponseMetaData responseMetaData `json:"response_metadata"`
 		SlackResponse
 	}{}
-	err = postSlackMethod(ctx, api.httpclient, "conversations.list", values, &response, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "conversations.list", values, &response, api)
 	if err != nil {
 		return nil, "", err
 	}
@@ -513,7 +513,7 @@ func (api *Client) OpenConversationContext(ctx context.Context, params *OpenConv
 		AlreadyOpen bool     `json:"already_open"`
 		SlackResponse
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.open", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.open", values, &response, api)
 	if err != nil {
 		return nil, false, false, err
 	}
@@ -537,7 +537,7 @@ func (api *Client) JoinConversationContext(ctx context.Context, channelID string
 		} `json:"response_metadata"`
 		SlackResponse
 	}{}
-	err := postSlackMethod(ctx, api.httpclient, "conversations.join", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.join", values, &response, api)
 	if err != nil {
 		return nil, "", nil, err
 	}
@@ -599,12 +599,10 @@ func (api *Client) GetConversationHistoryContext(ctx context.Context, params *Ge
 
 	response := GetConversationHistoryResponse{}
 
-	err := postSlackMethod(ctx, api.httpclient, "conversations.history", values, &response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "conversations.history", values, &response, api)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return &response, nil
+
+	return &response, response.Err()
 }
diff --git a/vendor/github.com/nlopes/slack/dialog.go b/vendor/github.com/nlopes/slack/dialog.go
index d1435d54..2e45a06c 100644
--- a/vendor/github.com/nlopes/slack/dialog.go
+++ b/vendor/github.com/nlopes/slack/dialog.go
@@ -36,8 +36,9 @@ type DialogTrigger struct {
 // Dialog as in Slack dialogs
 // https://api.slack.com/dialogs#option_element_attributes#top-level_dialog_attributes
 type Dialog struct {
-	TriggerID      string          `json:"trigger_id"`  //Required
-	CallbackID     string          `json:"callback_id"` //Required
+	TriggerID      string          `json:"trigger_id"`      // Required
+	CallbackID     string          `json:"callback_id"`     // Required
+	State          string          `json:"state,omitempty"` // Optional
 	Title          string          `json:"title"`
 	SubmitLabel    string          `json:"submit_label,omitempty"`
 	NotifyOnCancel bool            `json:"notify_on_cancel"`
@@ -47,30 +48,13 @@ type Dialog struct {
 // DialogElement abstract type for dialogs.
 type DialogElement interface{}
 
-// DialogCallback is sent from Slack when a user submits a form from within a dialog
-type DialogCallback struct {
-	Type        string            `json:"type"`
-	CallbackID  string            `json:"callback_id"`
-	Team        Team              `json:"team"`
-	Channel     Channel           `json:"channel"`
-	User        User              `json:"user"`
-	ActionTs    string            `json:"action_ts"`
-	Token       string            `json:"token"`
-	ResponseURL string            `json:"response_url"`
-	Submission  map[string]string `json:"submission"`
-}
+// DialogCallback DEPRECATED use InteractionCallback
+type DialogCallback InteractionCallback
 
-// DialogSuggestionCallback is sent from Slack when a user types in a select field with an external data source
-type DialogSuggestionCallback struct {
-	Type        string  `json:"type"`
-	Token       string  `json:"token"`
-	ActionTs    string  `json:"action_ts"`
-	Team        Team    `json:"team"`
-	User        User    `json:"user"`
-	Channel     Channel `json:"channel"`
-	ElementName string  `json:"name"`
-	Value       string  `json:"value"`
-	CallbackID  string  `json:"callback_id"`
+// DialogSubmissionCallback is sent from Slack when a user submits a form from within a dialog
+type DialogSubmissionCallback struct {
+	State      string            `json:"state,omitempty"`
+	Submission map[string]string `json:"submission"`
 }
 
 // DialogOpenResponse response from `dialog.open`
@@ -108,8 +92,8 @@ func (api *Client) OpenDialogContext(ctx context.Context, triggerID string, dial
 	}
 
 	response := &DialogOpenResponse{}
-	endpoint := SLACK_API + "dialog.open"
-	if err := postJSON(ctx, api.httpclient, endpoint, api.token, encoded, response, api.debug); err != nil {
+	endpoint := APIURL + "dialog.open"
+	if err := postJSON(ctx, api.httpclient, endpoint, api.token, encoded, response, api); err != nil {
 		return err
 	}
 
diff --git a/vendor/github.com/nlopes/slack/dialog_select.go b/vendor/github.com/nlopes/slack/dialog_select.go
index cff35479..ea95ccfa 100644
--- a/vendor/github.com/nlopes/slack/dialog_select.go
+++ b/vendor/github.com/nlopes/slack/dialog_select.go
@@ -24,6 +24,7 @@ type DialogInputSelect struct {
 	SelectedOptions string               `json:"selected_options,omitempty"` //Optional. Default value for "external" only
 	Options         []DialogSelectOption `json:"options,omitempty"`          //One of options or option_groups is required.
 	OptionGroups    []DialogOptionGroup  `json:"option_groups,omitempty"`    //Provide up to 100 options.
+	MinQueryLength  int                  `json:"min_query_length,omitempty"` //Optional. minimum characters before query is sent.
 }
 
 // DialogSelectOption is an option for the user to select from the menu
diff --git a/vendor/github.com/nlopes/slack/dnd.go b/vendor/github.com/nlopes/slack/dnd.go
index 26d36d6a..da6e4a16 100644
--- a/vendor/github.com/nlopes/slack/dnd.go
+++ b/vendor/github.com/nlopes/slack/dnd.go
@@ -36,9 +36,9 @@ type dndTeamInfoResponse struct {
 	SlackResponse
 }
 
-func dndRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*dndResponseFull, error) {
+func dndRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*dndResponseFull, error) {
 	response := &dndResponseFull{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
@@ -61,7 +61,7 @@ func (api *Client) EndDNDContext(ctx context.Context) error {
 
 	response := &SlackResponse{}
 
-	if err := postSlackMethod(ctx, api.httpclient, "dnd.endDnd", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "dnd.endDnd", values, response, api); err != nil {
 		return err
 	}
 
@@ -79,7 +79,7 @@ func (api *Client) EndSnoozeContext(ctx context.Context) (*DNDStatus, error) {
 		"token": {api.token},
 	}
 
-	response, err := dndRequest(ctx, api.httpclient, "dnd.endSnooze", values, api.debug)
+	response, err := dndRequest(ctx, api.httpclient, "dnd.endSnooze", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -100,7 +100,7 @@ func (api *Client) GetDNDInfoContext(ctx context.Context, user *string) (*DNDSta
 		values.Set("user", *user)
 	}
 
-	response, err := dndRequest(ctx, api.httpclient, "dnd.info", values, api.debug)
+	response, err := dndRequest(ctx, api.httpclient, "dnd.info", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -120,11 +120,12 @@ func (api *Client) GetDNDTeamInfoContext(ctx context.Context, users []string) (m
 	}
 	response := &dndTeamInfoResponse{}
 
-	if err := postSlackMethod(ctx, api.httpclient, "dnd.teamInfo", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "dnd.teamInfo", values, response, api); err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
+
+	if response.Err() != nil {
+		return nil, response.Err()
 	}
 	return response.Users, nil
 }
@@ -144,7 +145,7 @@ func (api *Client) SetSnoozeContext(ctx context.Context, minutes int) (*DNDStatu
 		"num_minutes": {strconv.Itoa(minutes)},
 	}
 
-	response, err := dndRequest(ctx, api.httpclient, "dnd.setSnooze", values, api.debug)
+	response, err := dndRequest(ctx, api.httpclient, "dnd.setSnooze", values, api)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/emoji.go b/vendor/github.com/nlopes/slack/emoji.go
index fe2945c4..aed2129f 100644
--- a/vendor/github.com/nlopes/slack/emoji.go
+++ b/vendor/github.com/nlopes/slack/emoji.go
@@ -23,7 +23,7 @@ func (api *Client) GetEmojiContext(ctx context.Context) (map[string]string, erro
 	}
 	response := &emojiResponseFull{}
 
-	err := postSlackMethod(ctx, api.httpclient, "emoji.list", values, response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "emoji.list", values, response, api)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/files.go b/vendor/github.com/nlopes/slack/files.go
index 0550c9fb..13158582 100644
--- a/vendor/github.com/nlopes/slack/files.go
+++ b/vendor/github.com/nlopes/slack/files.go
@@ -137,16 +137,14 @@ func NewGetFilesParameters() GetFilesParameters {
 	}
 }
 
-func fileRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*fileResponseFull, error) {
+func fileRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*fileResponseFull, error) {
 	response := &fileResponseFull{}
-	err := postForm(ctx, client, SLACK_API+path, values, response, debug)
+	err := postForm(ctx, client, APIURL+path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+
+	return response, response.Err()
 }
 
 // GetFileInfo retrieves a file and related comments
@@ -163,7 +161,7 @@ func (api *Client) GetFileInfoContext(ctx context.Context, fileID string, count,
 		"page":  {strconv.Itoa(page)},
 	}
 
-	response, err := fileRequest(ctx, api.httpclient, "files.info", values, api.debug)
+	response, err := fileRequest(ctx, api.httpclient, "files.info", values, api)
 	if err != nil {
 		return nil, nil, nil, err
 	}
@@ -202,7 +200,7 @@ func (api *Client) GetFilesContext(ctx context.Context, params GetFilesParameter
 		values.Add("page", strconv.Itoa(params.Page))
 	}
 
-	response, err := fileRequest(ctx, api.httpclient, "files.list", values, api.debug)
+	response, err := fileRequest(ctx, api.httpclient, "files.list", values, api)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -246,19 +244,17 @@ func (api *Client) UploadFileContext(ctx context.Context, params FileUploadParam
 	}
 	if params.Content != "" {
 		values.Add("content", params.Content)
-		err = postForm(ctx, api.httpclient, SLACK_API+"files.upload", values, response, api.debug)
+		err = postForm(ctx, api.httpclient, APIURL+"files.upload", values, response, api)
 	} else if params.File != "" {
-		err = postLocalWithMultipartResponse(ctx, api.httpclient, "files.upload", params.File, "file", values, response, api.debug)
+		err = postLocalWithMultipartResponse(ctx, api.httpclient, "files.upload", params.File, "file", values, response, api)
 	} else if params.Reader != nil {
-		err = postWithMultipartResponse(ctx, api.httpclient, "files.upload", params.Filename, "file", values, params.Reader, response, api.debug)
+		err = postWithMultipartResponse(ctx, api.httpclient, "files.upload", params.Filename, "file", values, params.Reader, response, api)
 	}
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return &response.File, nil
+
+	return &response.File, response.Err()
 }
 
 // DeleteFileComment deletes a file's comment
@@ -277,7 +273,7 @@ func (api *Client) DeleteFileCommentContext(ctx context.Context, fileID, comment
 		"file":  {fileID},
 		"id":    {commentID},
 	}
-	_, err = fileRequest(ctx, api.httpclient, "files.comments.delete", values, api.debug)
+	_, err = fileRequest(ctx, api.httpclient, "files.comments.delete", values, api)
 	return err
 }
 
@@ -293,7 +289,7 @@ func (api *Client) DeleteFileContext(ctx context.Context, fileID string) (err er
 		"file":  {fileID},
 	}
 
-	_, err = fileRequest(ctx, api.httpclient, "files.delete", values, api.debug)
+	_, err = fileRequest(ctx, api.httpclient, "files.delete", values, api)
 	return err
 }
 
@@ -309,7 +305,7 @@ func (api *Client) RevokeFilePublicURLContext(ctx context.Context, fileID string
 		"file":  {fileID},
 	}
 
-	response, err := fileRequest(ctx, api.httpclient, "files.revokePublicURL", values, api.debug)
+	response, err := fileRequest(ctx, api.httpclient, "files.revokePublicURL", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -328,7 +324,7 @@ func (api *Client) ShareFilePublicURLContext(ctx context.Context, fileID string)
 		"file":  {fileID},
 	}
 
-	response, err := fileRequest(ctx, api.httpclient, "files.sharedPublicURL", values, api.debug)
+	response, err := fileRequest(ctx, api.httpclient, "files.sharedPublicURL", values, api)
 	if err != nil {
 		return nil, nil, nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/groups.go b/vendor/github.com/nlopes/slack/groups.go
index 67e78e99..a248f6fd 100644
--- a/vendor/github.com/nlopes/slack/groups.go
+++ b/vendor/github.com/nlopes/slack/groups.go
@@ -2,7 +2,6 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"net/url"
 	"strconv"
 )
@@ -28,16 +27,14 @@ type groupResponseFull struct {
 	SlackResponse
 }
 
-func groupRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*groupResponseFull, error) {
+func groupRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*groupResponseFull, error) {
 	response := &groupResponseFull{}
-	err := postForm(ctx, client, SLACK_API+path, values, response, debug)
+	err := postForm(ctx, client, APIURL+path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+
+	return response, response.Err()
 }
 
 // ArchiveGroup archives a private group
@@ -52,7 +49,7 @@ func (api *Client) ArchiveGroupContext(ctx context.Context, group string) error
 		"channel": {group},
 	}
 
-	_, err := groupRequest(ctx, api.httpclient, "groups.archive", values, api.debug)
+	_, err := groupRequest(ctx, api.httpclient, "groups.archive", values, api)
 	return err
 }
 
@@ -68,7 +65,7 @@ func (api *Client) UnarchiveGroupContext(ctx context.Context, group string) erro
 		"channel": {group},
 	}
 
-	_, err := groupRequest(ctx, api.httpclient, "groups.unarchive", values, api.debug)
+	_, err := groupRequest(ctx, api.httpclient, "groups.unarchive", values, api)
 	return err
 }
 
@@ -84,7 +81,7 @@ func (api *Client) CreateGroupContext(ctx context.Context, group string) (*Group
 		"name":  {group},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.create", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.create", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -109,7 +106,7 @@ func (api *Client) CreateChildGroupContext(ctx context.Context, group string) (*
 		"channel": {group},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.createChild", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.createChild", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -128,7 +125,7 @@ func (api *Client) CloseGroupContext(ctx context.Context, group string) (bool, b
 		"channel": {group},
 	}
 
-	response, err := imRequest(ctx, api.httpclient, "groups.close", values, api.debug)
+	response, err := imRequest(ctx, api.httpclient, "groups.close", values, api)
 	if err != nil {
 		return false, false, err
 	}
@@ -170,7 +167,7 @@ func (api *Client) GetGroupHistoryContext(ctx context.Context, group string, par
 		}
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.history", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.history", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -190,7 +187,7 @@ func (api *Client) InviteUserToGroupContext(ctx context.Context, group, user str
 		"user":    {user},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.invite", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.invite", values, api)
 	if err != nil {
 		return nil, false, err
 	}
@@ -209,7 +206,7 @@ func (api *Client) LeaveGroupContext(ctx context.Context, group string) (err err
 		"channel": {group},
 	}
 
-	_, err = groupRequest(ctx, api.httpclient, "groups.leave", values, api.debug)
+	_, err = groupRequest(ctx, api.httpclient, "groups.leave", values, api)
 	return err
 }
 
@@ -226,7 +223,7 @@ func (api *Client) KickUserFromGroupContext(ctx context.Context, group, user str
 		"user":    {user},
 	}
 
-	_, err = groupRequest(ctx, api.httpclient, "groups.kick", values, api.debug)
+	_, err = groupRequest(ctx, api.httpclient, "groups.kick", values, api)
 	return err
 }
 
@@ -244,7 +241,7 @@ func (api *Client) GetGroupsContext(ctx context.Context, excludeArchived bool) (
 		values.Add("exclude_archived", "1")
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.list", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.list", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -263,7 +260,7 @@ func (api *Client) GetGroupInfoContext(ctx context.Context, group string) (*Grou
 		"channel": {group},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.info", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.info", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -288,7 +285,7 @@ func (api *Client) SetGroupReadMarkContext(ctx context.Context, group, ts string
 		"ts":      {ts},
 	}
 
-	_, err = groupRequest(ctx, api.httpclient, "groups.mark", values, api.debug)
+	_, err = groupRequest(ctx, api.httpclient, "groups.mark", values, api)
 	return err
 }
 
@@ -304,7 +301,7 @@ func (api *Client) OpenGroupContext(ctx context.Context, group string) (bool, bo
 		"channel": {group},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.open", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.open", values, api)
 	if err != nil {
 		return false, false, err
 	}
@@ -328,7 +325,7 @@ func (api *Client) RenameGroupContext(ctx context.Context, group, name string) (
 
 	// XXX: the created entry in this call returns a string instead of a number
 	// so I may have to do some workaround to solve it.
-	response, err := groupRequest(ctx, api.httpclient, "groups.rename", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.rename", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -348,7 +345,7 @@ func (api *Client) SetGroupPurposeContext(ctx context.Context, group, purpose st
 		"purpose": {purpose},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.setPurpose", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.setPurpose", values, api)
 	if err != nil {
 		return "", err
 	}
@@ -368,7 +365,7 @@ func (api *Client) SetGroupTopicContext(ctx context.Context, group, topic string
 		"topic":   {topic},
 	}
 
-	response, err := groupRequest(ctx, api.httpclient, "groups.setTopic", values, api.debug)
+	response, err := groupRequest(ctx, api.httpclient, "groups.setTopic", values, api)
 	if err != nil {
 		return "", err
 	}
diff --git a/vendor/github.com/nlopes/slack/im.go b/vendor/github.com/nlopes/slack/im.go
index fa8b0959..10563d91 100644
--- a/vendor/github.com/nlopes/slack/im.go
+++ b/vendor/github.com/nlopes/slack/im.go
@@ -2,7 +2,6 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"net/url"
 	"strconv"
 )
@@ -29,16 +28,14 @@ type IM struct {
 	IsUserDeleted bool   `json:"is_user_deleted"`
 }
 
-func imRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*imResponseFull, error) {
+func imRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*imResponseFull, error) {
 	response := &imResponseFull{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+
+	return response, response.Err()
 }
 
 // CloseIMChannel closes the direct message channel
@@ -53,7 +50,7 @@ func (api *Client) CloseIMChannelContext(ctx context.Context, channel string) (b
 		"channel": {channel},
 	}
 
-	response, err := imRequest(ctx, api.httpclient, "im.close", values, api.debug)
+	response, err := imRequest(ctx, api.httpclient, "im.close", values, api)
 	if err != nil {
 		return false, false, err
 	}
@@ -74,7 +71,7 @@ func (api *Client) OpenIMChannelContext(ctx context.Context, user string) (bool,
 		"user":  {user},
 	}
 
-	response, err := imRequest(ctx, api.httpclient, "im.open", values, api.debug)
+	response, err := imRequest(ctx, api.httpclient, "im.open", values, api)
 	if err != nil {
 		return false, false, "", err
 	}
@@ -94,7 +91,7 @@ func (api *Client) MarkIMChannelContext(ctx context.Context, channel, ts string)
 		"ts":      {ts},
 	}
 
-	_, err := imRequest(ctx, api.httpclient, "im.mark", values, api.debug)
+	_, err := imRequest(ctx, api.httpclient, "im.mark", values, api)
 	return err
 }
 
@@ -133,7 +130,7 @@ func (api *Client) GetIMHistoryContext(ctx context.Context, channel string, para
 		}
 	}
 
-	response, err := imRequest(ctx, api.httpclient, "im.history", values, api.debug)
+	response, err := imRequest(ctx, api.httpclient, "im.history", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -151,7 +148,7 @@ func (api *Client) GetIMChannelsContext(ctx context.Context) ([]IM, error) {
 		"token": {api.token},
 	}
 
-	response, err := imRequest(ctx, api.httpclient, "im.list", values, api.debug)
+	response, err := imRequest(ctx, api.httpclient, "im.list", values, api)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/interactions.go b/vendor/github.com/nlopes/slack/interactions.go
new file mode 100644
index 00000000..97e31a49
--- /dev/null
+++ b/vendor/github.com/nlopes/slack/interactions.go
@@ -0,0 +1,31 @@
+package slack
+
+// InteractionType type of interactions
+type InteractionType string
+
+// Types of interactions that can be received.
+const (
+	InteractionTypeDialogSubmission   = InteractionType("dialog_submission")
+	InteractionTypeDialogSuggestion   = InteractionType("dialog_suggestion")
+	InteractionTypeInteractionMessage = InteractionType("interactive_message")
+	InteractionTypeMessageAction      = InteractionType("message_action")
+)
+
+// InteractionCallback is sent from slack when a user interactions with a button or dialog.
+type InteractionCallback struct {
+	Type            InteractionType `json:"type"`
+	Token           string          `json:"token"`
+	CallbackID      string          `json:"callback_id"`
+	ResponseURL     string          `json:"response_url"`
+	TriggerID       string          `json:"trigger_id"`
+	ActionTs        string          `json:"action_ts"`
+	Team            Team            `json:"team"`
+	Channel         Channel         `json:"channel"`
+	User            User            `json:"user"`
+	OriginalMessage Message         `json:"original_message"`
+	Message         Message         `json:"message"`
+	Name            string          `json:"name"`
+	Value           string          `json:"value"`
+	ActionCallback
+	DialogSubmissionCallback
+}
diff --git a/vendor/github.com/nlopes/slack/logger.go b/vendor/github.com/nlopes/slack/logger.go
index 501d1672..6a3533a9 100644
--- a/vendor/github.com/nlopes/slack/logger.go
+++ b/vendor/github.com/nlopes/slack/logger.go
@@ -2,52 +2,59 @@ package slack
 
 import (
 	"fmt"
-	"sync"
 )
 
-// SetLogger let's library users supply a logger, so that api debugging
-// can be logged along with the application's debugging info.
-func SetLogger(l logProvider) {
-	loggerMutex.Lock()
-	logger = ilogger{logProvider: l}
-	loggerMutex.Unlock()
-}
-
-var (
-	loggerMutex = new(sync.Mutex)
-	logger      logInternal // A logger that can be set by consumers
-)
-
-// logProvider is a logger interface compatible with both stdlib and some
-// 3rd party loggers such as logrus.
-type logProvider interface {
+// logger is a logger interface compatible with both stdlib and some
+// 3rd party loggers.
+type logger interface {
 	Output(int, string) error
 }
 
-// logInternal represents the internal logging api we use.
-type logInternal interface {
+// ilogger represents the internal logging api we use.
+type ilogger interface {
+	logger
 	Print(...interface{})
 	Printf(string, ...interface{})
 	Println(...interface{})
-	Output(int, string) error
 }
 
-// ilogger implements the additional methods used by our internal logging.
-type ilogger struct {
-	logProvider
+type debug interface {
+	Debug() bool
+
+	// Debugf print a formatted debug line.
+	Debugf(format string, v ...interface{})
+	// Debugln print a debug line.
+	Debugln(v ...interface{})
+}
+
+// internalLog implements the additional methods used by our internal logging.
+type internalLog struct {
+	logger
 }
 
 // Println replicates the behaviour of the standard logger.
-func (t ilogger) Println(v ...interface{}) {
+func (t internalLog) Println(v ...interface{}) {
 	t.Output(2, fmt.Sprintln(v...))
 }
 
 // Printf replicates the behaviour of the standard logger.
-func (t ilogger) Printf(format string, v ...interface{}) {
+func (t internalLog) Printf(format string, v ...interface{}) {
 	t.Output(2, fmt.Sprintf(format, v...))
 }
 
 // Print replicates the behaviour of the standard logger.
-func (t ilogger) Print(v ...interface{}) {
+func (t internalLog) Print(v ...interface{}) {
 	t.Output(2, fmt.Sprint(v...))
 }
+
+type discard struct{}
+
+func (t discard) Debug() bool {
+	return false
+}
+
+// Debugf print a formatted debug line.
+func (t discard) Debugf(format string, v ...interface{}) {}
+
+// Debugln print a debug line.
+func (t discard) Debugln(v ...interface{}) {}
diff --git a/vendor/github.com/nlopes/slack/messages.go b/vendor/github.com/nlopes/slack/messages.go
index 6551dd4f..bde9a37e 100644
--- a/vendor/github.com/nlopes/slack/messages.go
+++ b/vendor/github.com/nlopes/slack/messages.go
@@ -4,11 +4,12 @@ package slack
 type OutgoingMessage struct {
 	ID int `json:"id"`
 	// channel ID
-	Channel         string `json:"channel,omitempty"`
-	Text            string `json:"text,omitempty"`
-	Type            string `json:"type,omitempty"`
-	ThreadTimestamp string `json:"thread_ts,omitempty"`
-	ThreadBroadcast bool   `json:"reply_broadcast,omitempty"`
+	Channel         string   `json:"channel,omitempty"`
+	Text            string   `json:"text,omitempty"`
+	Type            string   `json:"type,omitempty"`
+	ThreadTimestamp string   `json:"thread_ts,omitempty"`
+	ThreadBroadcast bool     `json:"reply_broadcast,omitempty"`
+	IDs             []string `json:"ids,omitempty"`
 }
 
 // Message is an auxiliary type to allow us to have a message containing sub messages
@@ -147,6 +148,15 @@ func (rtm *RTM) NewOutgoingMessage(text string, channelID string, options ...RTM
 	return &msg
 }
 
+// NewSubscribeUserPresence prepares an OutgoingMessage that the user can
+// use to subscribe presence events for the specified users.
+func (rtm *RTM) NewSubscribeUserPresence(ids []string) *OutgoingMessage {
+	return &OutgoingMessage{
+		Type: "presence_sub",
+		IDs:  ids,
+	}
+}
+
 // NewTypingMessage prepares an OutgoingMessage that the user can
 // use to send as a typing indicator. Use this function to properly set the
 // messageID.
@@ -174,5 +184,4 @@ func RTMsgOptionBroadcast() RTMsgOption {
 	return func(msg *OutgoingMessage) {
 		msg.ThreadBroadcast = true
 	}
-
 }
diff --git a/vendor/github.com/nlopes/slack/misc.go b/vendor/github.com/nlopes/slack/misc.go
index 69103384..30ae4628 100644
--- a/vendor/github.com/nlopes/slack/misc.go
+++ b/vendor/github.com/nlopes/slack/misc.go
@@ -19,6 +19,7 @@ import (
 	"time"
 )
 
+// SlackResponse handles parsing out errors from the web api.
 type SlackResponse struct {
 	Ok    bool   `json:"ok"`
 	Error string `json:"error"`
@@ -64,47 +65,31 @@ func (e *RateLimitedError) Error() string {
 	return fmt.Sprintf("Slack rate limit exceeded, retry after %s", e.RetryAfter)
 }
 
-func fileUploadReq(ctx context.Context, path, fieldname, filename string, values url.Values, r io.Reader) (*http.Request, error) {
-	body := &bytes.Buffer{}
-	wr := multipart.NewWriter(body)
+func fileUploadReq(ctx context.Context, path string, values url.Values, r io.Reader) (*http.Request, error) {
+	req, err := http.NewRequest("POST", path, r)
 
-	ioWriter, err := wr.CreateFormFile(fieldname, filename)
-	if err != nil {
-		wr.Close()
-		return nil, err
-	}
-	_, err = io.Copy(ioWriter, r)
-	if err != nil {
-		wr.Close()
-		return nil, err
-	}
-	// Close the multipart writer or the footer won't be written
-	wr.Close()
-	req, err := http.NewRequest("POST", path, body)
 	req = req.WithContext(ctx)
 	if err != nil {
 		return nil, err
 	}
-	req.Header.Add("Content-Type", wr.FormDataContentType())
 	req.URL.RawQuery = (values).Encode()
 	return req, nil
 }
 
-func parseResponseBody(body io.ReadCloser, intf interface{}, debug bool) error {
+func parseResponseBody(body io.ReadCloser, intf interface{}, d debug) error {
 	response, err := ioutil.ReadAll(body)
 	if err != nil {
 		return err
 	}
 
-	// FIXME: will be api.Debugf
-	if debug {
-		logger.Printf("parseResponseBody: %s\n", string(response))
+	if d.Debug() {
+		d.Debugln("parseResponseBody", string(response))
 	}
 
 	return json.Unmarshal(response, intf)
 }
 
-func postLocalWithMultipartResponse(ctx context.Context, client HTTPRequester, path, fpath, fieldname string, values url.Values, intf interface{}, debug bool) error {
+func postLocalWithMultipartResponse(ctx context.Context, client httpClient, path, fpath, fieldname string, values url.Values, intf interface{}, d debug) error {
 	fullpath, err := filepath.Abs(fpath)
 	if err != nil {
 		return err
@@ -114,16 +99,38 @@ func postLocalWithMultipartResponse(ctx context.Context, client HTTPRequester, p
 		return err
 	}
 	defer file.Close()
-	return postWithMultipartResponse(ctx, client, path, filepath.Base(fpath), fieldname, values, file, intf, debug)
+	return postWithMultipartResponse(ctx, client, path, filepath.Base(fpath), fieldname, values, file, intf, d)
 }
 
-func postWithMultipartResponse(ctx context.Context, client HTTPRequester, path, name, fieldname string, values url.Values, r io.Reader, intf interface{}, debug bool) error {
-	req, err := fileUploadReq(ctx, SLACK_API+path, fieldname, name, values, r)
+func postWithMultipartResponse(ctx context.Context, client httpClient, path, name, fieldname string, values url.Values, r io.Reader, intf interface{}, d debug) error {
+	pipeReader, pipeWriter := io.Pipe()
+	wr := multipart.NewWriter(pipeWriter)
+	errc := make(chan error)
+	go func() {
+		defer pipeWriter.Close()
+		ioWriter, err := wr.CreateFormFile(fieldname, name)
+		if err != nil {
+			errc <- err
+			return
+		}
+		_, err = io.Copy(ioWriter, r)
+		if err != nil {
+			errc <- err
+			return
+		}
+		if err = wr.Close(); err != nil {
+			errc <- err
+			return
+		}
+	}()
+	req, err := fileUploadReq(ctx, APIURL+path, values, pipeReader)
 	if err != nil {
 		return err
 	}
+	req.Header.Add("Content-Type", wr.FormDataContentType())
 	req = req.WithContext(ctx)
 	resp, err := client.Do(req)
+
 	if err != nil {
 		return err
 	}
@@ -139,14 +146,18 @@ func postWithMultipartResponse(ctx context.Context, client HTTPRequester, path,
 
 	// Slack seems to send an HTML body along with 5xx error codes. Don't parse it.
 	if resp.StatusCode != http.StatusOK {
-		logResponse(resp, debug)
+		logResponse(resp, d)
 		return statusCodeError{Code: resp.StatusCode, Status: resp.Status}
 	}
-
-	return parseResponseBody(resp.Body, intf, debug)
+	select {
+	case err = <-errc:
+		return err
+	default:
+		return parseResponseBody(resp.Body, intf, d)
+	}
 }
 
-func doPost(ctx context.Context, client HTTPRequester, req *http.Request, intf interface{}, debug bool) error {
+func doPost(ctx context.Context, client httpClient, req *http.Request, intf interface{}, d debug) error {
 	req = req.WithContext(ctx)
 	resp, err := client.Do(req)
 	if err != nil {
@@ -164,15 +175,15 @@ func doPost(ctx context.Context, client HTTPRequester, req *http.Request, intf i
 
 	// Slack seems to send an HTML body along with 5xx error codes. Don't parse it.
 	if resp.StatusCode != http.StatusOK {
-		logResponse(resp, debug)
+		logResponse(resp, d)
 		return statusCodeError{Code: resp.StatusCode, Status: resp.Status}
 	}
 
-	return parseResponseBody(resp.Body, intf, debug)
+	return parseResponseBody(resp.Body, intf, d)
 }
 
 // post JSON.
-func postJSON(ctx context.Context, client HTTPRequester, endpoint, token string, json []byte, intf interface{}, debug bool) error {
+func postJSON(ctx context.Context, client httpClient, endpoint, token string, json []byte, intf interface{}, d debug) error {
 	reqBody := bytes.NewBuffer(json)
 	req, err := http.NewRequest("POST", endpoint, reqBody)
 	if err != nil {
@@ -180,38 +191,53 @@ func postJSON(ctx context.Context, client HTTPRequester, endpoint, token string,
 	}
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
-	return doPost(ctx, client, req, intf, debug)
+	return doPost(ctx, client, req, intf, d)
 }
 
 // post a url encoded form.
-func postForm(ctx context.Context, client HTTPRequester, endpoint string, values url.Values, intf interface{}, debug bool) error {
+func postForm(ctx context.Context, client httpClient, endpoint string, values url.Values, intf interface{}, d debug) error {
 	reqBody := strings.NewReader(values.Encode())
 	req, err := http.NewRequest("POST", endpoint, reqBody)
 	if err != nil {
 		return err
 	}
 	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
-	return doPost(ctx, client, req, intf, debug)
+	return doPost(ctx, client, req, intf, d)
 }
 
 // post to a slack web method.
-func postSlackMethod(ctx context.Context, client HTTPRequester, path string, values url.Values, intf interface{}, debug bool) error {
-	return postForm(ctx, client, SLACK_API+path, values, intf, debug)
+func postSlackMethod(ctx context.Context, client httpClient, path string, values url.Values, intf interface{}, d debug) error {
+	return postForm(ctx, client, APIURL+path, values, intf, d)
 }
 
-func parseAdminResponse(ctx context.Context, client HTTPRequester, method string, teamName string, values url.Values, intf interface{}, debug bool) error {
-	endpoint := fmt.Sprintf(SLACK_WEB_API_FORMAT, teamName, method, time.Now().Unix())
-	return postForm(ctx, client, endpoint, values, intf, debug)
+// get a slack web method.
+func getSlackMethod(ctx context.Context, client httpClient, path string, values url.Values, intf interface{}, d debug) error {
+	return getResource(ctx, client, APIURL+path, values, intf, d)
 }
 
-func logResponse(resp *http.Response, debug bool) error {
-	if debug {
+func getResource(ctx context.Context, client httpClient, endpoint string, values url.Values, intf interface{}, d debug) error {
+	req, err := http.NewRequest("GET", endpoint, nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.URL.RawQuery = values.Encode()
+
+	return doPost(ctx, client, req, intf, d)
+}
+
+func parseAdminResponse(ctx context.Context, client httpClient, method string, teamName string, values url.Values, intf interface{}, d debug) error {
+	endpoint := fmt.Sprintf(WEBAPIURLFormat, teamName, method, time.Now().Unix())
+	return postForm(ctx, client, endpoint, values, intf, d)
+}
+
+func logResponse(resp *http.Response, d debug) error {
+	if d.Debug() {
 		text, err := httputil.DumpResponse(resp, true)
 		if err != nil {
 			return err
 		}
-
-		logger.Print(string(text))
+		d.Debugln(string(text))
 	}
 
 	return nil
diff --git a/vendor/github.com/nlopes/slack/oauth.go b/vendor/github.com/nlopes/slack/oauth.go
index 378af4a5..8a8194cb 100644
--- a/vendor/github.com/nlopes/slack/oauth.go
+++ b/vendor/github.com/nlopes/slack/oauth.go
@@ -2,10 +2,10 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"net/url"
 )
 
+// OAuthResponseIncomingWebhook ...
 type OAuthResponseIncomingWebhook struct {
 	URL              string `json:"url"`
 	Channel          string `json:"channel"`
@@ -13,11 +13,13 @@ type OAuthResponseIncomingWebhook struct {
 	ConfigurationURL string `json:"configuration_url"`
 }
 
+// OAuthResponseBot ...
 type OAuthResponseBot struct {
 	BotUserID      string `json:"bot_user_id"`
 	BotAccessToken string `json:"bot_access_token"`
 }
 
+// OAuthResponse ...
 type OAuthResponse struct {
 	AccessToken     string                       `json:"access_token"`
 	Scope           string                       `json:"scope"`
@@ -30,24 +32,24 @@ type OAuthResponse struct {
 }
 
 // GetOAuthToken retrieves an AccessToken
-func GetOAuthToken(clientID, clientSecret, code, redirectURI string, debug bool) (accessToken string, scope string, err error) {
-	return GetOAuthTokenContext(context.Background(), clientID, clientSecret, code, redirectURI, debug)
+func GetOAuthToken(client httpClient, clientID, clientSecret, code, redirectURI string) (accessToken string, scope string, err error) {
+	return GetOAuthTokenContext(context.Background(), client, clientID, clientSecret, code, redirectURI)
 }
 
 // GetOAuthTokenContext retrieves an AccessToken with a custom context
-func GetOAuthTokenContext(ctx context.Context, clientID, clientSecret, code, redirectURI string, debug bool) (accessToken string, scope string, err error) {
-	response, err := GetOAuthResponseContext(ctx, clientID, clientSecret, code, redirectURI, debug)
+func GetOAuthTokenContext(ctx context.Context, client httpClient, clientID, clientSecret, code, redirectURI string) (accessToken string, scope string, err error) {
+	response, err := GetOAuthResponseContext(ctx, client, clientID, clientSecret, code, redirectURI)
 	if err != nil {
 		return "", "", err
 	}
 	return response.AccessToken, response.Scope, nil
 }
 
-func GetOAuthResponse(clientID, clientSecret, code, redirectURI string, debug bool) (resp *OAuthResponse, err error) {
-	return GetOAuthResponseContext(context.Background(), clientID, clientSecret, code, redirectURI, debug)
+func GetOAuthResponse(client httpClient, clientID, clientSecret, code, redirectURI string) (resp *OAuthResponse, err error) {
+	return GetOAuthResponseContext(context.Background(), client, clientID, clientSecret, code, redirectURI)
 }
 
-func GetOAuthResponseContext(ctx context.Context, clientID, clientSecret, code, redirectURI string, debug bool) (resp *OAuthResponse, err error) {
+func GetOAuthResponseContext(ctx context.Context, client httpClient, clientID, clientSecret, code, redirectURI string) (resp *OAuthResponse, err error) {
 	values := url.Values{
 		"client_id":     {clientID},
 		"client_secret": {clientSecret},
@@ -55,12 +57,8 @@ func GetOAuthResponseContext(ctx context.Context, clientID, clientSecret, code,
 		"redirect_uri":  {redirectURI},
 	}
 	response := &OAuthResponse{}
-	err = postSlackMethod(ctx, customHTTPClient, "oauth.access", values, response, debug)
-	if err != nil {
+	if err = postSlackMethod(ctx, client, "oauth.access", values, response, discard{}); err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+	return response, response.Err()
 }
diff --git a/vendor/github.com/nlopes/slack/pins.go b/vendor/github.com/nlopes/slack/pins.go
index 34863f17..c1d525df 100644
--- a/vendor/github.com/nlopes/slack/pins.go
+++ b/vendor/github.com/nlopes/slack/pins.go
@@ -34,7 +34,7 @@ func (api *Client) AddPinContext(ctx context.Context, channel string, item ItemR
 	}
 
 	response := &SlackResponse{}
-	if err := postSlackMethod(ctx, api.httpclient, "pins.add", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "pins.add", values, response, api); err != nil {
 		return err
 	}
 
@@ -63,7 +63,7 @@ func (api *Client) RemovePinContext(ctx context.Context, channel string, item It
 	}
 
 	response := &SlackResponse{}
-	if err := postSlackMethod(ctx, api.httpclient, "pins.remove", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "pins.remove", values, response, api); err != nil {
 		return err
 	}
 
@@ -83,7 +83,7 @@ func (api *Client) ListPinsContext(ctx context.Context, channel string) ([]Item,
 	}
 
 	response := &listPinsResponseFull{}
-	err := postSlackMethod(ctx, api.httpclient, "pins.list", values, response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "pins.list", values, response, api)
 	if err != nil {
 		return nil, nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/reactions.go b/vendor/github.com/nlopes/slack/reactions.go
index 5eabde63..abe1e72a 100644
--- a/vendor/github.com/nlopes/slack/reactions.go
+++ b/vendor/github.com/nlopes/slack/reactions.go
@@ -155,7 +155,7 @@ func (api *Client) AddReactionContext(ctx context.Context, name string, item Ite
 	}
 
 	response := &SlackResponse{}
-	if err := postSlackMethod(ctx, api.httpclient, "reactions.add", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "reactions.add", values, response, api); err != nil {
 		return err
 	}
 
@@ -189,7 +189,7 @@ func (api *Client) RemoveReactionContext(ctx context.Context, name string, item
 	}
 
 	response := &SlackResponse{}
-	if err := postSlackMethod(ctx, api.httpclient, "reactions.remove", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "reactions.remove", values, response, api); err != nil {
 		return err
 	}
 
@@ -223,7 +223,7 @@ func (api *Client) GetReactionsContext(ctx context.Context, item ItemRef, params
 	}
 
 	response := &getReactionsResponseFull{}
-	if err := postSlackMethod(ctx, api.httpclient, "reactions.get", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "reactions.get", values, response, api); err != nil {
 		return nil, err
 	}
 	if !response.Ok {
@@ -256,7 +256,7 @@ func (api *Client) ListReactionsContext(ctx context.Context, params ListReaction
 	}
 
 	response := &listReactionsResponseFull{}
-	err := postSlackMethod(ctx, api.httpclient, "reactions.list", values, response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "reactions.list", values, response, api)
 	if err != nil {
 		return nil, nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/rtm.go b/vendor/github.com/nlopes/slack/rtm.go
index 41a136eb..e7fa83f7 100644
--- a/vendor/github.com/nlopes/slack/rtm.go
+++ b/vendor/github.com/nlopes/slack/rtm.go
@@ -38,7 +38,7 @@ func (api *Client) StartRTM() (info *Info, websocketURL string, err error) {
 // To have a fully managed Websocket connection, use `NewRTM`, and call `ManageConnection()` on it.
 func (api *Client) StartRTMContext(ctx context.Context) (info *Info, websocketURL string, err error) {
 	response := &infoResponseFull{}
-	err = postSlackMethod(ctx, api.httpclient, "rtm.start", url.Values{"token": {api.token}}, response, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "rtm.start", url.Values{"token": {api.token}}, response, api)
 	if err != nil {
 		return nil, "", err
 	}
@@ -63,7 +63,7 @@ func (api *Client) ConnectRTM() (info *Info, websocketURL string, err error) {
 // To have a fully managed Websocket connection, use `NewRTM`, and call `ManageConnection()` on it.
 func (api *Client) ConnectRTMContext(ctx context.Context) (info *Info, websocketURL string, err error) {
 	response := &infoResponseFull{}
-	err = postSlackMethod(ctx, api.httpclient, "rtm.connect", url.Values{"token": {api.token}}, response, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "rtm.connect", url.Values{"token": {api.token}}, response, api)
 	if err != nil {
 		api.Debugf("Failed to connect to RTM: %s", err)
 		return nil, "", err
@@ -100,17 +100,24 @@ func RTMOptionPingInterval(d time.Duration) RTMOption {
 	}
 }
 
+// RTMOptionConnParams installs parameters to embed into the connection URL.
+func RTMOptionConnParams(connParams url.Values) RTMOption {
+	return func(rtm *RTM) {
+		rtm.connParams = connParams
+	}
+}
+
 // NewRTM returns a RTM, which provides a fully managed connection to
 // Slack's websocket-based Real-Time Messaging protocol.
 func (api *Client) NewRTM(options ...RTMOption) *RTM {
 	result := &RTM{
 		Client:           *api,
+		wasIntentional:   true,
+		isConnected:      false,
 		IncomingEvents:   make(chan RTMEvent, 50),
 		outgoingMessages: make(chan OutgoingMessage, 20),
 		pingInterval:     defaultPingInterval,
 		pingDeadman:      time.NewTimer(deadmanDuration(defaultPingInterval)),
-		isConnected:      false,
-		wasIntentional:   true,
 		killChannel:      make(chan bool),
 		disconnected:     make(chan struct{}, 1),
 		forcePing:        make(chan bool),
@@ -125,14 +132,3 @@ func (api *Client) NewRTM(options ...RTMOption) *RTM {
 
 	return result
 }
-
-// NewRTMWithOptions Deprecated just use NewRTM(RTMOptionsUseStart(true))
-// returns a RTM, which provides a fully managed connection to
-// Slack's websocket-based Real-Time Messaging protocol.
-// This also allows to configure various options available for RTM API.
-func (api *Client) NewRTMWithOptions(options *RTMOptions) *RTM {
-	if options != nil {
-		return api.NewRTM(RTMOptionUseStart(options.UseRTMStart))
-	}
-	return api.NewRTM()
-}
diff --git a/vendor/github.com/nlopes/slack/search.go b/vendor/github.com/nlopes/slack/search.go
index e858952f..2d018fcc 100644
--- a/vendor/github.com/nlopes/slack/search.go
+++ b/vendor/github.com/nlopes/slack/search.go
@@ -2,7 +2,6 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"net/url"
 	"strconv"
 )
@@ -104,14 +103,12 @@ func (api *Client) _search(ctx context.Context, path, query string, params Searc
 	}
 
 	response = &searchResponseFull{}
-	err := postSlackMethod(ctx, api.httpclient, path, values, response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, path, values, response, api)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+
+	return response, response.Err()
 
 }
 
diff --git a/vendor/github.com/nlopes/slack/security.go b/vendor/github.com/nlopes/slack/security.go
index 50201d99..6ab3c698 100644
--- a/vendor/github.com/nlopes/slack/security.go
+++ b/vendor/github.com/nlopes/slack/security.go
@@ -1,47 +1,99 @@
-package slack

-

-import (

-	"crypto/hmac"

-	"crypto/sha256"

-	"encoding/hex"

-	"errors"

-	"fmt"

-	"hash"

-	"net/http"

-)

-

-// SecretsVerifier contains the information needed to verify that the request comes from Slack

-type SecretsVerifier struct {

-	slackSig  string

-	timeStamp string

-	hmac      hash.Hash

-}

-

-// NewSecretsVerifier returns a SecretsVerifier object in exchange for an http.Header object and signing secret

-func NewSecretsVerifier(header http.Header, signingSecret string) (SecretsVerifier, error) {

-	if header["X-Slack-Signature"][0] == "" || header["X-Slack-Request-Timestamp"][0] == "" {

-		return SecretsVerifier{}, errors.New("Headers are empty, cannot create SecretsVerifier")

-	}

-

-	hash := hmac.New(sha256.New, []byte(signingSecret))

-	hash.Write([]byte(fmt.Sprintf("v0:%s:", header["X-Slack-Request-Timestamp"][0])))

-	return SecretsVerifier{

-		slackSig:  header["X-Slack-Signature"][0],

-		timeStamp: header["X-Slack-Request-Timestamp"][0],

-		hmac:      hash,

-	}, nil

-}

-

-func (v *SecretsVerifier) Write(body []byte) (n int, err error) {

-	return v.hmac.Write(body)

-}

-

-// Ensure compares the signature sent from Slack with the actual computed hash to judge validity

-func (v SecretsVerifier) Ensure() error {

-	computed := "v0=" + string(hex.EncodeToString(v.hmac.Sum(nil)))

-	if computed == v.slackSig {

-		return nil

-	}

-

-	return fmt.Errorf("Expected signing signature: %s, but computed: %s", v.slackSig, computed)

-}

+package slack
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"hash"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Signature headers
+const (
+	hSignature = "X-Slack-Signature"
+	hTimestamp = "X-Slack-Request-Timestamp"
+)
+
+// SecretsVerifier contains the information needed to verify that the request comes from Slack
+type SecretsVerifier struct {
+	signature []byte
+	hmac      hash.Hash
+}
+
+func unsafeSignatureVerifier(header http.Header, secret string) (_ SecretsVerifier, err error) {
+	var (
+		bsignature []byte
+	)
+
+	signature := header.Get(hSignature)
+	stimestamp := header.Get(hTimestamp)
+
+	if signature == "" || stimestamp == "" {
+		return SecretsVerifier{}, errors.New("missing headers")
+	}
+
+	if bsignature, err = hex.DecodeString(strings.TrimPrefix(signature, "v0=")); err != nil {
+		return SecretsVerifier{}, err
+	}
+
+	hash := hmac.New(sha256.New, []byte(secret))
+	hash.Write([]byte(fmt.Sprintf("v0:%s:", stimestamp)))
+
+	return SecretsVerifier{
+		signature: bsignature,
+		hmac:      hash,
+	}, nil
+}
+
+// NewSecretsVerifier returns a SecretsVerifier object in exchange for an http.Header object and signing secret
+func NewSecretsVerifier(header http.Header, secret string) (sv SecretsVerifier, err error) {
+	var (
+		timestamp int64
+	)
+
+	stimestamp := header.Get(hTimestamp)
+
+	if sv, err = unsafeSignatureVerifier(header, secret); err != nil {
+		return SecretsVerifier{}, err
+	}
+
+	if timestamp, err = strconv.ParseInt(stimestamp, 10, 64); err != nil {
+		return SecretsVerifier{}, err
+	}
+
+	diff := absDuration(time.Now().Sub(time.Unix(timestamp, 0)))
+	if diff > 5*time.Minute {
+		return SecretsVerifier{}, fmt.Errorf("timestamp is too old")
+	}
+
+	return sv, err
+}
+
+func (v *SecretsVerifier) Write(body []byte) (n int, err error) {
+	return v.hmac.Write(body)
+}
+
+// Ensure compares the signature sent from Slack with the actual computed hash to judge validity
+func (v SecretsVerifier) Ensure() error {
+	computed := v.hmac.Sum(nil)
+	// use hmac.Equal prevent leaking timing information.
+	if hmac.Equal(computed, v.signature) {
+		return nil
+	}
+
+	return fmt.Errorf("Expected signing signature: %s, but computed: %s", v.signature, computed)
+}
+
+func abs64(n int64) int64 {
+	y := n >> 63
+	return (n ^ y) - y
+}
+
+func absDuration(n time.Duration) time.Duration {
+	return time.Duration(abs64(int64(n)))
+}
diff --git a/vendor/github.com/nlopes/slack/slack.go b/vendor/github.com/nlopes/slack/slack.go
index 6d1e7de9..1e75142d 100644
--- a/vendor/github.com/nlopes/slack/slack.go
+++ b/vendor/github.com/nlopes/slack/slack.go
@@ -2,7 +2,6 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"log"
 	"net/http"
@@ -10,31 +9,17 @@ import (
 	"os"
 )
 
-// Added as a var so that we can change this for testing purposes
-var SLACK_API string = "https://slack.com/api/"
-var SLACK_WEB_API_FORMAT string = "https://%s.slack.com/api/users.admin.%s?t=%s"
+// APIURL a dded as a var so that we can change this for testing purposes
+var APIURL = "https://slack.com/api/"
 
-// HTTPClient sets a custom http.Client
-// deprecated: in favor of SetHTTPClient()
-var HTTPClient = &http.Client{}
+// WEBAPIURLFormat ...
+const WEBAPIURLFormat = "https://%s.slack.com/api/users.admin.%s?t=%d"
 
-var customHTTPClient HTTPRequester = HTTPClient
-
-// HTTPRequester defines the minimal interface needed for an http.Client to be implemented.
-//
-// Use it in conjunction with the SetHTTPClient function to allow for other capabilities
-// like a tracing http.Client
-type HTTPRequester interface {
+// httpClient defines the minimal interface needed for an http.Client to be implemented.
+type httpClient interface {
 	Do(*http.Request) (*http.Response, error)
 }
 
-// SetHTTPClient allows you to specify a custom http.Client
-// Use this instead of the package level HTTPClient variable if you want to use a custom client like the
-// Stackdriver Trace HTTPClient https://godoc.org/cloud.google.com/go/trace#HTTPClient
-func SetHTTPClient(client HTTPRequester) {
-	customHTTPClient = client
-}
-
 // ResponseMetadata holds pagination metadata
 type ResponseMetadata struct {
 	Cursor string `json:"next_cursor"`
@@ -48,6 +33,7 @@ func (t *ResponseMetadata) initialize() *ResponseMetadata {
 	return &ResponseMetadata{}
 }
 
+// AuthTestResponse ...
 type AuthTestResponse struct {
 	URL    string `json:"url"`
 	Team   string `json:"team"`
@@ -61,20 +47,36 @@ type authTestResponseFull struct {
 	AuthTestResponse
 }
 
+// Client for the slack api.
 type Client struct {
 	token      string
 	info       Info
 	debug      bool
-	httpclient HTTPRequester
+	log        ilogger
+	httpclient httpClient
 }
 
 // Option defines an option for a Client
 type Option func(*Client)
 
 // OptionHTTPClient - provide a custom http client to the slack client.
-func OptionHTTPClient(c HTTPRequester) func(*Client) {
-	return func(s *Client) {
-		s.httpclient = c
+func OptionHTTPClient(client httpClient) func(*Client) {
+	return func(c *Client) {
+		c.httpclient = client
+	}
+}
+
+// OptionDebug enable debugging for the client
+func OptionDebug(b bool) func(*Client) {
+	return func(c *Client) {
+		c.debug = b
+	}
+}
+
+// OptionLog set logging for client.
+func OptionLog(l logger) func(*Client) {
+	return func(c *Client) {
+		c.log = internalLog{logger: l}
 	}
 }
 
@@ -82,7 +84,8 @@ func OptionHTTPClient(c HTTPRequester) func(*Client) {
 func New(token string, options ...Option) *Client {
 	s := &Client{
 		token:      token,
-		httpclient: customHTTPClient,
+		httpclient: &http.Client{},
+		log:        log.New(os.Stderr, "nlopes/slack", log.LstdFlags|log.Lshortfile),
 	}
 
 	for _, opt := range options {
@@ -98,43 +101,32 @@ func (api *Client) AuthTest() (response *AuthTestResponse, error error) {
 }
 
 // AuthTestContext tests if the user is able to do authenticated requests or not with a custom context
-func (api *Client) AuthTestContext(ctx context.Context) (response *AuthTestResponse, error error) {
+func (api *Client) AuthTestContext(ctx context.Context) (response *AuthTestResponse, err error) {
 	api.Debugf("Challenging auth...")
 	responseFull := &authTestResponseFull{}
-	err := postSlackMethod(ctx, api.httpclient, "auth.test", url.Values{"token": {api.token}}, responseFull, api.debug)
+	err = postSlackMethod(ctx, api.httpclient, "auth.test", url.Values{"token": {api.token}}, responseFull, api)
 	if err != nil {
-		api.Debugf("failed to test for auth: %s", err)
 		return nil, err
 	}
-	if !responseFull.Ok {
-		api.Debugf("auth response was not Ok: %s", responseFull.Error)
-		return nil, errors.New(responseFull.Error)
-	}
 
-	api.Debugf("Auth challenge was successful with response %+v", responseFull.AuthTestResponse)
-	return &responseFull.AuthTestResponse, nil
-}
-
-// SetDebug switches the api into debug mode
-// When in debug mode, it logs various info about what its doing
-// If you ever use this in production, don't call SetDebug(true)
-func (api *Client) SetDebug(debug bool) {
-	api.debug = debug
-	if debug && logger == nil {
-		SetLogger(log.New(os.Stdout, "nlopes/slack", log.LstdFlags|log.Lshortfile))
-	}
+	return &responseFull.AuthTestResponse, responseFull.Err()
 }
 
 // Debugf print a formatted debug line.
 func (api *Client) Debugf(format string, v ...interface{}) {
 	if api.debug {
-		logger.Output(2, fmt.Sprintf(format, v...))
+		api.log.Output(2, fmt.Sprintf(format, v...))
 	}
 }
 
 // Debugln print a debug line.
 func (api *Client) Debugln(v ...interface{}) {
 	if api.debug {
-		logger.Output(2, fmt.Sprintln(v...))
+		api.log.Output(2, fmt.Sprintln(v...))
 	}
 }
+
+// Debug returns if debug is enabled.
+func (api *Client) Debug() bool {
+	return api.debug
+}
diff --git a/vendor/github.com/nlopes/slack/stars.go b/vendor/github.com/nlopes/slack/stars.go
index c1e2f6cb..7e1e621d 100644
--- a/vendor/github.com/nlopes/slack/stars.go
+++ b/vendor/github.com/nlopes/slack/stars.go
@@ -58,7 +58,7 @@ func (api *Client) AddStarContext(ctx context.Context, channel string, item Item
 	}
 
 	response := &SlackResponse{}
-	if err := postSlackMethod(ctx, api.httpclient, "stars.add", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "stars.add", values, response, api); err != nil {
 		return err
 	}
 
@@ -87,7 +87,7 @@ func (api *Client) RemoveStarContext(ctx context.Context, channel string, item I
 	}
 
 	response := &SlackResponse{}
-	if err := postSlackMethod(ctx, api.httpclient, "stars.remove", values, response, api.debug); err != nil {
+	if err := postSlackMethod(ctx, api.httpclient, "stars.remove", values, response, api); err != nil {
 		return err
 	}
 
@@ -115,7 +115,7 @@ func (api *Client) ListStarsContext(ctx context.Context, params StarsParameters)
 	}
 
 	response := &listResponseFull{}
-	err := postSlackMethod(ctx, api.httpclient, "stars.list", values, response, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "stars.list", values, response, api)
 	if err != nil {
 		return nil, nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/team.go b/vendor/github.com/nlopes/slack/team.go
index b6e341eb..1892cf5f 100644
--- a/vendor/github.com/nlopes/slack/team.go
+++ b/vendor/github.com/nlopes/slack/team.go
@@ -2,7 +2,6 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"net/url"
 	"strconv"
 )
@@ -67,44 +66,33 @@ func NewAccessLogParameters() AccessLogParameters {
 	}
 }
 
-func teamRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*TeamResponse, error) {
+func teamRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*TeamResponse, error) {
 	response := &TeamResponse{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
 
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-
-	return response, nil
+	return response, response.Err()
 }
 
-func billableInfoRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (map[string]BillingActive, error) {
+func billableInfoRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (map[string]BillingActive, error) {
 	response := &BillableInfoResponse{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
 
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-
-	return response.BillableInfo, nil
+	return response.BillableInfo, response.Err()
 }
 
-func accessLogsRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*LoginResponse, error) {
+func accessLogsRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*LoginResponse, error) {
 	response := &LoginResponse{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+	return response, response.Err()
 }
 
 // GetTeamInfo gets the Team Information of the user
@@ -118,7 +106,7 @@ func (api *Client) GetTeamInfoContext(ctx context.Context) (*TeamInfo, error) {
 		"token": {api.token},
 	}
 
-	response, err := teamRequest(ctx, api.httpclient, "team.info", values, api.debug)
+	response, err := teamRequest(ctx, api.httpclient, "team.info", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -142,7 +130,7 @@ func (api *Client) GetAccessLogsContext(ctx context.Context, params AccessLogPar
 		values.Add("page", strconv.Itoa(params.Page))
 	}
 
-	response, err := accessLogsRequest(ctx, api.httpclient, "team.accessLogs", values, api.debug)
+	response, err := accessLogsRequest(ctx, api.httpclient, "team.accessLogs", values, api)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -159,7 +147,7 @@ func (api *Client) GetBillableInfoContext(ctx context.Context, user string) (map
 		"user":  {user},
 	}
 
-	return billableInfoRequest(ctx, api.httpclient, "team.billableInfo", values, api.debug)
+	return billableInfoRequest(ctx, api.httpclient, "team.billableInfo", values, api)
 }
 
 // GetBillableInfoForTeam returns the billing_active status of all users on the team.
@@ -173,5 +161,5 @@ func (api *Client) GetBillableInfoForTeamContext(ctx context.Context) (map[strin
 		"token": {api.token},
 	}
 
-	return billableInfoRequest(ctx, api.httpclient, "team.billableInfo", values, api.debug)
+	return billableInfoRequest(ctx, api.httpclient, "team.billableInfo", values, api)
 }
diff --git a/vendor/github.com/nlopes/slack/usergroups.go b/vendor/github.com/nlopes/slack/usergroups.go
index cc9bc4ca..9e145272 100644
--- a/vendor/github.com/nlopes/slack/usergroups.go
+++ b/vendor/github.com/nlopes/slack/usergroups.go
@@ -2,7 +2,6 @@ package slack
 
 import (
 	"context"
-	"errors"
 	"net/url"
 	"strings"
 )
@@ -41,16 +40,14 @@ type userGroupResponseFull struct {
 	SlackResponse
 }
 
-func userGroupRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*userGroupResponseFull, error) {
+func userGroupRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*userGroupResponseFull, error) {
 	response := &userGroupResponseFull{}
-	err := postSlackMethod(ctx, client, path, values, response, debug)
+	err := postSlackMethod(ctx, client, path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+
+	return response, response.Err()
 }
 
 // CreateUserGroup creates a new user group
@@ -77,7 +74,7 @@ func (api *Client) CreateUserGroupContext(ctx context.Context, userGroup UserGro
 		values["channels"] = []string{strings.Join(userGroup.Prefs.Channels, ",")}
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.create", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.create", values, api)
 	if err != nil {
 		return UserGroup{}, err
 	}
@@ -96,7 +93,7 @@ func (api *Client) DisableUserGroupContext(ctx context.Context, userGroup string
 		"usergroup": {userGroup},
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.disable", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.disable", values, api)
 	if err != nil {
 		return UserGroup{}, err
 	}
@@ -115,7 +112,7 @@ func (api *Client) EnableUserGroupContext(ctx context.Context, userGroup string)
 		"usergroup": {userGroup},
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.enable", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.enable", values, api)
 	if err != nil {
 		return UserGroup{}, err
 	}
@@ -179,7 +176,7 @@ func (api *Client) GetUserGroupsContext(ctx context.Context, options ...GetUserG
 		values.Add("include_users", "true")
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.list", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.list", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -210,7 +207,7 @@ func (api *Client) UpdateUserGroupContext(ctx context.Context, userGroup UserGro
 		values["description"] = []string{userGroup.Description}
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.update", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.update", values, api)
 	if err != nil {
 		return UserGroup{}, err
 	}
@@ -229,7 +226,7 @@ func (api *Client) GetUserGroupMembersContext(ctx context.Context, userGroup str
 		"usergroup": {userGroup},
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.users.list", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.users.list", values, api)
 	if err != nil {
 		return []string{}, err
 	}
@@ -249,7 +246,7 @@ func (api *Client) UpdateUserGroupMembersContext(ctx context.Context, userGroup
 		"users":     {members},
 	}
 
-	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.users.update", values, api.debug)
+	response, err := userGroupRequest(ctx, api.httpclient, "usergroups.users.update", values, api)
 	if err != nil {
 		return UserGroup{}, err
 	}
diff --git a/vendor/github.com/nlopes/slack/users.go b/vendor/github.com/nlopes/slack/users.go
index 0dd20db5..aa941a74 100644
--- a/vendor/github.com/nlopes/slack/users.go
+++ b/vendor/github.com/nlopes/slack/users.go
@@ -189,16 +189,14 @@ func NewUserSetPhotoParams() UserSetPhotoParams {
 	}
 }
 
-func userRequest(ctx context.Context, client HTTPRequester, path string, values url.Values, debug bool) (*userResponseFull, error) {
+func userRequest(ctx context.Context, client httpClient, path string, values url.Values, d debug) (*userResponseFull, error) {
 	response := &userResponseFull{}
-	err := postForm(ctx, client, SLACK_API+path, values, response, debug)
+	err := postForm(ctx, client, APIURL+path, values, response, d)
 	if err != nil {
 		return nil, err
 	}
-	if !response.Ok {
-		return nil, errors.New(response.Error)
-	}
-	return response, nil
+
+	return response, response.Err()
 }
 
 // GetUserPresence will retrieve the current presence status of given user.
@@ -213,7 +211,7 @@ func (api *Client) GetUserPresenceContext(ctx context.Context, user string) (*Us
 		"user":  {user},
 	}
 
-	response, err := userRequest(ctx, api.httpclient, "users.getPresence", values, api.debug)
+	response, err := userRequest(ctx, api.httpclient, "users.getPresence", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -232,7 +230,7 @@ func (api *Client) GetUserInfoContext(ctx context.Context, user string) (*User,
 		"user":  {user},
 	}
 
-	response, err := userRequest(ctx, api.httpclient, "users.info", values, api.debug)
+	response, err := userRequest(ctx, api.httpclient, "users.info", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -310,7 +308,7 @@ func (t UserPagination) Next(ctx context.Context) (_ UserPagination, err error)
 		"cursor":   {t.previousResp.Cursor},
 	}
 
-	if resp, err = userRequest(ctx, t.c.httpclient, "users.list", values, t.c.debug); err != nil {
+	if resp, err = userRequest(ctx, t.c.httpclient, "users.list", values, t.c); err != nil {
 		return t, err
 	}
 
@@ -355,7 +353,7 @@ func (api *Client) GetUserByEmailContext(ctx context.Context, email string) (*Us
 		"token": {api.token},
 		"email": {email},
 	}
-	response, err := userRequest(ctx, api.httpclient, "users.lookupByEmail", values, api.debug)
+	response, err := userRequest(ctx, api.httpclient, "users.lookupByEmail", values, api)
 	if err != nil {
 		return nil, err
 	}
@@ -373,7 +371,7 @@ func (api *Client) SetUserAsActiveContext(ctx context.Context) (err error) {
 		"token": {api.token},
 	}
 
-	_, err = userRequest(ctx, api.httpclient, "users.setActive", values, api.debug)
+	_, err = userRequest(ctx, api.httpclient, "users.setActive", values, api)
 	return err
 }
 
@@ -389,7 +387,7 @@ func (api *Client) SetUserPresenceContext(ctx context.Context, presence string)
 		"presence": {presence},
 	}
 
-	_, err := userRequest(ctx, api.httpclient, "users.setPresence", values, api.debug)
+	_, err := userRequest(ctx, api.httpclient, "users.setPresence", values, api)
 	return err
 }
 
@@ -405,7 +403,7 @@ func (api *Client) GetUserIdentityContext(ctx context.Context) (*UserIdentityRes
 	}
 	response := &UserIdentityResponse{}
 
-	err := postForm(ctx, api.httpclient, SLACK_API+"users.identity", values, response, api.debug)
+	err := postForm(ctx, api.httpclient, APIURL+"users.identity", values, response, api)
 	if err != nil {
 		return nil, err
 	}
@@ -436,7 +434,7 @@ func (api *Client) SetUserPhotoContext(ctx context.Context, image string, params
 		values.Add("crop_w", strconv.Itoa(params.CropW))
 	}
 
-	err := postLocalWithMultipartResponse(ctx, api.httpclient, "users.setPhoto", image, "image", values, response, api.debug)
+	err := postLocalWithMultipartResponse(ctx, api.httpclient, "users.setPhoto", image, "image", values, response, api)
 	if err != nil {
 		return err
 	}
@@ -456,7 +454,7 @@ func (api *Client) DeleteUserPhotoContext(ctx context.Context) error {
 		"token": {api.token},
 	}
 
-	err := postForm(ctx, api.httpclient, SLACK_API+"users.deletePhoto", values, response, api.debug)
+	err := postForm(ctx, api.httpclient, APIURL+"users.deletePhoto", values, response, api)
 	if err != nil {
 		return err
 	}
@@ -506,7 +504,7 @@ func (api *Client) SetUserCustomStatusContext(ctx context.Context, statusText, s
 	}
 
 	response := &userResponseFull{}
-	if err = postForm(ctx, api.httpclient, SLACK_API+"users.profile.set", values, response, api.debug); err != nil {
+	if err = postForm(ctx, api.httpclient, APIURL+"users.profile.set", values, response, api); err != nil {
 		return err
 	}
 
@@ -547,7 +545,7 @@ func (api *Client) GetUserProfileContext(ctx context.Context, userID string, inc
 	}
 	resp := &getUserProfileResponse{}
 
-	err := postSlackMethod(ctx, api.httpclient, "users.profile.get", values, &resp, api.debug)
+	err := postSlackMethod(ctx, api.httpclient, "users.profile.get", values, &resp, api)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/github.com/nlopes/slack/websocket.go b/vendor/github.com/nlopes/slack/websocket.go
index 242acf40..ec810a9b 100644
--- a/vendor/github.com/nlopes/slack/websocket.go
+++ b/vendor/github.com/nlopes/slack/websocket.go
@@ -3,6 +3,7 @@ package slack
 import (
 	"encoding/json"
 	"errors"
+	"net/url"
 	"sync"
 	"time"
 
@@ -20,6 +21,9 @@ const (
 //
 // Create this element with Client's NewRTM() or NewRTMWithOptions(*RTMOptions)
 type RTM struct {
+	// Client is the main API, embedded
+	Client
+
 	idGen        IDGenerator
 	pingInterval time.Duration
 	pingDeadman  *time.Timer
@@ -35,8 +39,6 @@ type RTM struct {
 	wasIntentional   bool
 	isConnected      bool
 
-	// Client is the main API, embedded
-	Client
 	websocketURL string
 
 	// UserDetails upon connection
@@ -53,18 +55,9 @@ type RTM struct {
 
 	// mu is mutex used to prevent RTM connection race conditions
 	mu *sync.Mutex
-}
 
-// RTMOptions allows configuration of various options available for RTM messaging
-//
-// This structure will evolve in time so please make sure you are always using the
-// named keys for every entry available as per Go 1 compatibility promise adding fields
-// to this structure should not be considered a breaking change.
-type RTMOptions struct {
-	// UseRTMStart set to true in order to use rtm.start or false to use rtm.connect
-	// As of 11th July 2017 you should prefer setting this to false, see:
-	// https://api.slack.com/changelog/2017-04-start-using-rtm-connect-and-stop-using-rtm-start
-	UseRTMStart bool
+	// connParams is a map of flags for connection parameters.
+	connParams url.Values
 }
 
 // Disconnect and wait, blocking until a successful disconnection.
diff --git a/vendor/github.com/nlopes/slack/websocket_managed_conn.go b/vendor/github.com/nlopes/slack/websocket_managed_conn.go
index e8ab65a1..62157910 100644
--- a/vendor/github.com/nlopes/slack/websocket_managed_conn.go
+++ b/vendor/github.com/nlopes/slack/websocket_managed_conn.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	stdurl "net/url"
 	"reflect"
 	"time"
 
@@ -157,6 +158,14 @@ func (rtm *RTM) startRTMAndDial(useRTMStart bool) (info *Info, _ *websocket.Conn
 		return nil, nil, err
 	}
 
+	// install connection parameters
+	u, err := stdurl.Parse(url)
+	if err != nil {
+		return nil, nil, err
+	}
+	u.RawQuery = rtm.connParams.Encode()
+	url = u.String()
+
 	rtm.Debugf("Dialing to websocket on url %s", url)
 	// Only use HTTPS for connections to prevent MITM attacks on the connection.
 	upgradeHeader := http.Header{}
@@ -274,7 +283,7 @@ func (rtm *RTM) sendWithDeadline(msg interface{}) error {
 // and instead lets a future failed 'PING' detect the failed connection.
 func (rtm *RTM) sendOutgoingMessage(msg OutgoingMessage) {
 	rtm.Debugln("Sending message:", msg)
-	if len(msg.Text) > MaxMessageTextLength {
+	if len([]rune(msg.Text)) > MaxMessageTextLength {
 		rtm.IncomingEvents <- RTMEvent{"outgoing_error", &MessageTooLongEvent{
 			Message:   msg,
 			MaxLength: MaxMessageTextLength,
@@ -405,8 +414,7 @@ func (rtm *RTM) handlePong(event json.RawMessage) {
 	rtm.resetDeadman()
 
 	if err := json.Unmarshal(event, &p); err != nil {
-		logger.Println("RTM Error unmarshalling 'pong' event:", err)
-		rtm.Debugln(" -> Erroneous 'ping' event:", string(event))
+		rtm.Client.log.Println("RTM Error unmarshalling 'pong' event:", err)
 		return
 	}
 
@@ -423,8 +431,8 @@ func (rtm *RTM) handlePong(event json.RawMessage) {
 func (rtm *RTM) handleEvent(typeStr string, event json.RawMessage) {
 	v, exists := EventMapping[typeStr]
 	if !exists {
-		rtm.Debugf("RTM Error, received unmapped event %q: %s\n", typeStr, string(event))
-		err := fmt.Errorf("RTM Error: Received unmapped event %q: %s\n", typeStr, string(event))
+		rtm.Debugf("RTM Error - received unmapped event %q: %s\n", typeStr, string(event))
+		err := fmt.Errorf("RTM Error: Received unmapped event %q: %s", typeStr, string(event))
 		rtm.IncomingEvents <- RTMEvent{"unmarshalling_error", &UnmarshallingErrorEvent{err}}
 		return
 	}
@@ -433,7 +441,7 @@ func (rtm *RTM) handleEvent(typeStr string, event json.RawMessage) {
 	err := json.Unmarshal(event, recvEvent)
 	if err != nil {
 		rtm.Debugf("RTM Error, could not unmarshall event %q: %s\n", typeStr, string(event))
-		err := fmt.Errorf("RTM Error: Could not unmarshall event %q: %s\n", typeStr, string(event))
+		err := fmt.Errorf("RTM Error: Could not unmarshall event %q: %s", typeStr, string(event))
 		rtm.IncomingEvents <- RTMEvent{"unmarshalling_error", &UnmarshallingErrorEvent{err}}
 		return
 	}
diff --git a/vendor/github.com/nlopes/slack/websocket_misc.go b/vendor/github.com/nlopes/slack/websocket_misc.go
index 16f48c74..bfcc805e 100644
--- a/vendor/github.com/nlopes/slack/websocket_misc.go
+++ b/vendor/github.com/nlopes/slack/websocket_misc.go
@@ -43,9 +43,10 @@ type HelloEvent struct{}
 
 // PresenceChangeEvent represents the presence change event
 type PresenceChangeEvent struct {
-	Type     string `json:"type"`
-	Presence string `json:"presence"`
-	User     string `json:"user"`
+	Type     string   `json:"type"`
+	Presence string   `json:"presence"`
+	User     string   `json:"user"`
+	Users    []string `json:"users"`
 }
 
 // UserTypingEvent represents the user typing event
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 84e4822f..a665570f 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -96,7 +96,7 @@ github.com/nicksnyder/go-i18n/i18n
 github.com/nicksnyder/go-i18n/i18n/bundle
 github.com/nicksnyder/go-i18n/i18n/language
 github.com/nicksnyder/go-i18n/i18n/translation
-# github.com/nlopes/slack v0.4.0
+# github.com/nlopes/slack v0.4.1-0.20181111125009-5963eafd777b
 github.com/nlopes/slack
 github.com/nlopes/slack/slackutilsx
 # github.com/paulrosania/go-charset v0.0.0-20151028000031-621bb39fcc83