private function createEditForm(CustomFieldsGroup $entity)
    {
        $form = $this->createForm('custom_fields_group', $entity, array(
            'action' => $this->generateUrl('customfieldsgroup_update', array('id' => $entity->getId())),
            'method' => 'PUT',
        ));
        $form->add('submit', 'submit', array('label' => 'Update'));

        return $form;
    }