/**
  * Gets a app by its handle.
  *
  * @param string $appHandle
  *
  * @return PushNotifications_AppModel|null
  */
 public function getAppByHandle($appHandle)
 {
     $appRecord = PushNotifications_AppRecord::model()->findByAttributes(array('handle' => $appHandle));
     if ($appRecord) {
         return PushNotifications_AppModel::populateModel($appRecord);
     }
 }