public function postRating(Request $request)
 {
     $input = $request->only(['rating', 'article_id']);
     $input['user_id'] = Auth::id();
     if ($input['rating'] > 0 && $input['rating'] < 6) {
         if ($rating = Rating::where('user_id', '=', $input['user_id'])->where('article_id', '=', $input['article_id'])->first()) {
             $rating->update($input);
         } else {
             Rating::create($input);
         }
     }
     return response()->json(['result' => 'success']);
 }
 /**
  * Store a newly created resource in storage.
  *
  * @param  \Illuminate\Http\Request  $request
  * @return \Illuminate\Http\Response
  */
 public function store(Request $request)
 {
     return Rating::create($request->all());
 }