require_once('Connect.php');

class LoginModel extends Connect{
    private $username;
    private $password;

    public function __construct($username, $password) {
        $this->username = $username;
        $this->password = $password;
    }

    public function getUser() {
        db();
    }

    public function login() {

    }
}

$loginModel = new LoginModel($_POST['displayName'], $_POST['password']);
$loginModel->getUser();

class Connect {
    private $servername;
    private $username;
    private $password;

    public function __construct() {
        $this->servername = 'localhost';
        $this->username = 'root';
        $this->password = '';
    }

    public function db() {
        try {
            $conn = new PDO("mysql:host=$this->servername;dbname=test",  $this->username, $this->password);
            $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
         }catch(PDOException $e) {
            die("Connection failed" . $e->getMessage());
        }
    }
}