public function authenticate()
{
$mapper = new Application_Model_UsersMapper();
$checkUser = $mapper->fetchAll($this->_user);
if (!$checkUser) {
$newUser = new Application_Model_Users(array('user' => $this->_user));
$result = $mapper->create($newUser);
}
return new Zend_Auth_Result(Zend_Auth_Result::SUCCESS, $this->_user);
}