public function actionCaption()
 {
     Yii::$app->response->format = Response::FORMAT_JSON;
     if (!Yii::$app->request->isAjax) {
         throw new BadRequestHttpException();
     }
     $response = false;
     $model = GalleryFile::findOne(Yii::$app->request->post('id'));
     $model->caption = Yii::$app->request->post('caption');
     if ($model->save()) {
         $response = ['status' => true, 'message' => 'Success'];
     }
     return $response;
 }