Incubator seem not work on PHP7.2 Mongodb 4 Phalcon 3

[vietlib]

I have tried to install Phalcon 3 with PHP7 and MongoDB.

I have installed incubator and do follow:

• Set loader like below:

$loader->registerNamespaces([
    'Phalcon' => '/vendor/phalcon/incubator/Library/Phalcon/'
]);

• In service.php add

$di->set('mongo', function () {
    $mongo = new Phalcon\Db\Adapter\MongoDB\Client("mongodb://localhost:27017");
    return $mongo->selectDatabase('database name');
}, true);

• Add model: Users

use Phalcon\Mvc\MongoCollection;

class Users extends MongoCollection
{
    public $username;
    public $password;
    public $fullname;
    public $dob;
    public $gender;
    public $avatar;
    public $cellphone;
    public $address;
    public $locktime;
    public $rolename;
    public $income;
    public $profit;

    public function getSource()
    {
        return 'users';
    }
}

• Add controller:

public function indexAction()
{
    $users= new Users();
    $users->username = 'Voltron';

    $users->save();
 }

However the error :

Fatal error: Class 'Phalcon\Mvc\MongoCollection' not found in C:\laragon\www\projectname\app\models\Users.php on line 11

Anybody help me, please.