FEATURE: proper mailing list mode

once enable_mailing_list_mode is enabled any user can elect
to get every post via email unless they opt out of category or topic

lib/topic_creator.rb

@@ -39,7 +39,6 @@ class TopicCreator
       @topic.notifier.watch_topic!(id, nil)
     end
 
-    TopicUser.auto_watch_new_topic(@topic.id)
     CategoryUser.auto_watch_new_topic(@topic)
   end