Add support for github app authorization (google#959)

Author: MorrisLaw

github/event.go

@@ -46,6 +46,8 @@ func (e *Event) ParsePayload() (payload interface{}, err error) {
 		payload = &DeploymentStatusEvent{}
 	case "ForkEvent":
 		payload = &ForkEvent{}
+	case "GitHubAppAuthorizationEvent":
+		payload = &GitHubAppAuthorizationEvent{}
 	case "GollumEvent":
 		payload = &GollumEvent{}
 	case "InstallationEvent":

github/event_types.go

@@ -139,6 +139,18 @@ type ForkEvent struct {
 	Installation *Installation `json:"installation,omitempty"`
 }
 
+// GitHubAppAuthorizationEvent is triggered when a user's authorization for a
+// GitHub Application is revoked.
+//
+// GitHub API docs: https://developer.github.com/v3/activity/events/types/#githubappauthorizationevent
+type GitHubAppAuthorizationEvent struct {
+	// The action performed. Can be "revoked".
+	Action *string `json:"action,omitempty"`
+
+	// The following fields are only populated by Webhook events.
+	Sender *User `json:"sender,omitempty"`
+}
+
 // Page represents a single Wiki page.
 type Page struct {
 	PageName *string `json:"page_name,omitempty"`