public String createSubForum(User invoker, User moderator,
			String subForumName, String forumId) {
		for (int i = 0; i < forums.size(); i++) {
			if (forums.get(i).getId().equals(forumId))
				return forums.get(i).createSubForum(invoker, moderator,
						subForumName);
		}
		return null;

	}