private function createEditForm(MediaType $entity)
    {
        $form = $this->createForm(new MediaTypeType(), $entity, array(
            'action' => $this->generateUrl('mediatype_update', array('id' => $entity->getId())),
            'method' => 'PUT',
        ));

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

        return $form;
    }