/**
* Check whether the user already exists
* checks for email and username
*
* @param Core_Model_Abstract $user
* @return type
*/
public function userExists(Core_Model_Abstract $user)
{
return $this->_getReadAdapter()->fetchRow("SELECT * FROM " . $this->tbl_user . " WHERE (username = '******' OR email = '" . $user->getEmail() . "') AND user_id != '" . $user->getId() . "'");
}