public static function createUser(array $ei_user_tab, $guard_id, Doctrine_Connection $conn = null)
 {
     if ($conn == null) {
         $conn = Doctrine_Manager::connection();
     }
     $new_ei_user = new EiUser();
     $new_ei_user->setGuardId($guard_id);
     $new_ei_user->setRefId($ei_user_tab['ref_id']);
     $new_ei_user->setUserId($ei_user_tab['user_id']);
     $new_ei_user->setMatricule($ei_user_tab['matricule']);
     $new_ei_user->save();
     return $new_ei_user;
 }