def add_contributor container, user, subreddit
      friend_wrapper container: container, name: user, r: subreddit, type: "contributor"
    end
def add_contributor container, user, subreddit
      friend_wrapper container: container, name: user, r: subreddit, type: "contributor"
    end
Add a contributor to the subreddit

 @param (see #add_moderator)
 @return (see #clear_sessions)