public function createOrDelete($id)
{
$topic = Topic::find($id);
if (Favorite::isUserFavoritedTopic(Auth::user(), $topic)) {
Auth::user()->favoriteTopics()->detach($topic->id);
} else {
Auth::user()->favoriteTopics()->attach($topic->id);
Notification::notify('topic_favorite', Auth::user(), $topic->user, $topic);
}
Flash::success(lang('Operation succeeded.'));
return Redirect::route('topics.show', $topic->id);
}