public function actionIndex()
 {
     if (empty(Session::getSession()->nome)) {
         $this->layout = 'login';
         $this->render('login', ['model' => new Usuario()]);
     } else {
         $post = new Post();
         $post->usuario_id = Session::getSession()->id;
         return $this->render('index', ['usuarios' => Usuario::count(), 'post' => $post]);
     }
 }