add threads field to guild

Author: jonas747

structs.go

@@ -411,10 +411,13 @@ type Guild struct {
 	Presences []*Presence `json:"presences"`
 
 	// A list of channels in the guild.
-	// This field is only present in GUILD_CREATE events and websocket
-	// update events, and thus is only present in state-cached guilds.
+	// This field is only present in GUILD_CREATE events
 	Channels []*Channel `json:"channels"`
 
+	// All active threads in the guild that current user has permission to view
+	// This field is only present in GUILD_CREATE events
+	Threads []*Channel `json:"threads"`
+
 	// A list of voice states for the guild.
 	// This field is only present in GUILD_CREATE events and websocket
 	// update events, and thus is only present in state-cached guilds.