private function createEditForm(CustomField $entity, $type)
    {
        $form = $this->createForm('custom_field_choice', $entity, array(
            'action' => $this->generateUrl('customfield_update', array('id' => $entity->getId())),
            'method' => 'PUT',
            'type' => $type,
            'group_widget' => 'hidden' 
        ));

        $form->add('submit', 'submit', array('label' => 'Update'));

        return $form;
    }