/**
  * Display a listing of user conversations.
  *
  * @return Response
  */
 public function index($user_id)
 {
     $conversations_users = ConversationUser::where('user_id', $user_id)->lists('conversation_id');
     $conversations = array();
     if ($conversations_users) {
         $conversations = Conversation::whereIn('id', $conversations_users)->get();
     }
     return Response::json(['success' => true, 'result' => $conversations]);
 }