Hi, i'm trying to learn the Kohana's Auth module but login method always return false.

Controller:

<?php defined('SYSPATH') OR die('No Direct Script Access');
class Controller_Auth extends Controller {
    public function action_index() {
        if($_POST) {
            $this->login();
        }

        $this->template = View::factory('login');
        echo $this->template;
    }

    private function login() {
    $user = ORM::factory('user');

        $data = array('username' => 'wilson', 'password' => '123');
        if(!$user->login($data)) {
            echo 'FAILED!';
        }
    }

    private function logout() {

    }
}    
?>

Model:

<?php defined('SYSPATH')  or die('No direct script access.');
class Model_User extends Model_Auth_User {
}
?>