private function getDefaultGroupsId()
    {
        $em = $this->getDoctrine()->getManager();
        
        $customFieldsGroupIds = $em->createQuery('SELECT g.id FROM '
                . 'ChillCustomFieldsBundle:CustomFieldsDefaultGroup d '
                . 'JOIN d.customFieldsGroup g')
                ->getResult(Query::HYDRATE_SCALAR);
        
        $result = array();
        foreach ($customFieldsGroupIds as $row) {
            $result[] = $row['id'];
        }
        
        return $result;
    }