public function store(ArticleRequest $request)
 {
     $request_data = $request->all();
     if ($request->hasFile('image_file')) {
         $saveImage = true;
         $image_file = $request_data['image_file'];
         unset($request_data['image_file']);
         $request_data['image_name'] = $this->generateImageName($image_file->getClientOriginalExtension());
         $request_data['mime_type'] = $image_file->getClientMimeType();
     }
     $article = new Article($request_data);
     //Auto assign department_id for article
     $article->department()->associate(Auth::user()->department);
     //Auto assign user_id for article
     $article->user()->associate(Auth::user());
     $article->save();
     if ($saveImage) {
         $path = storage_path("app/articles/" . Auth::user()->articles->last()->id . "/");
         $this->saveImage($path, $image_file, $request_data['image_name']);
     }
     return redirect('articles');
 }