public function categoryFormSucceeded(UI\Form $form, $values)
 {
     $categoryId = $this->getParameter('id');
     if (isset($values['parent']) && !$values['parent']) {
         $values['parent'] = $values['parent'] ? $values['parent'] : null;
     }
     if ($categoryId) {
         $category = $this->category->get($categoryId);
         if (!$category) {
             $this->error('Data nebyla nalezena v databázi.', '404');
         } else {
             $category->update($values);
         }
         $this->flashMessage('Změny uloženy.', 'success');
     } else {
         $category = $this->category->insert($values);
         $this->flashMessage('Kategorie vložena do databáze.', 'success');
     }
     $this->redirect('edit', $category->id);
 }