public function update(Request $request, $id)
 {
     $news = WechatDepotNews::find($id);
     if (empty($news)) {
         return $this->failure_noexists();
     }
     $keys = 'title,author,description,content,cover_aid,cover_in_content,redirect,url';
     $data = $this->autoValidate($request, 'wechat-news.store', $keys);
     $news->update($data);
     return $this->success('', FALSE, $news->toArray());
 }