/**
  * Adds the user a permission from its name.
  *
  * @param string $name The permission name
  * @param Doctrine_Connection $con A Doctrine_Connection object
  * @throws sfException
  */
 public function addPermissionByName($name, $con = null)
 {
     $permission = Doctrine_Core::getTable('sfGuardPermission')->findOneByName($name);
     if (!$permission) {
         throw new sfException(sprintf('The permission "%s" does not exist.', $name));
     }
     $up = new sfGuardUserPermission();
     $up->setUser($this);
     $up->setPermission($permission);
     $up->save($con);
 }