user() public method

public user ( )
 /**
  * Store a newly created resource in storage.
  *
  * @param  \Illuminate\Http\Request  $request
  * @return \Illuminate\Http\Response
  */
 public function store(Request $request)
 {
     $token = JWTAuth::getToken();
     $user = JWTAuth::toUser($token);
     $validator = Validator::make($request->all(), ['title' => 'required|max:255', 'content' => 'required']);
     if ($validator->fails()) {
         return response()->json(['errors' => $validator->errors()], 400);
     }
     $topic = new Topic();
     $topic->title = $request->title;
     $topic->user()->associate($user);
     $topic->save();
     $post = new Post();
     $post->content = $request->content;
     $post->topic()->associate($topic);
     $post->user()->associate($user);
     $post->save();
     return response()->json(['topic' => $topic, 'post' => $post], 201);
 }