symfony 1.4 - Plugins | sfDoctrineGuardPlugin - set a group to user from frontend -

i need set group user in frontend application. here have done.

$g = sfguardgrouptable::getinstance()->findonebyid(1);  $u = new sfguarduser(); $u->setfirstname($request->getparameter('first_name')); $u->setlastname($request->getparameter('last_name')); $u->setemailaddress($request->getparameter('email_address'));   $u->setsfguardusergroup($g); $u->save(); 

the user inserted cannot set group user.

there's many many relation between sfguarduser , sfguardgroup, therefore each sfguarduser has collection of sfguardgroup objects. have collection , add group it:

$u->getsfguardusergroup()->add($g);