public function postEdit($req)
 {
     $c = new Category();
     $c->fill($_POST);
     $c->id = $req->id;
     $result = $c->save();
     if ($result) {
         $this->service->flash('The category was edited.', 'success');
     } else {
         $this->service->flash('Can\'t edit the category.', 'alert');
     }
     return $this->service->back();
 }