Debug in HomeController

<?php
namespace MyApp\Controllers;
use Phalcon\Mvc\View;
use MyApp\Model\Products;
use MyApp\Model\Posts;
use MyApp\Model\ProductCategories;
class HomeController extends ControllerBase
{
    public function indexAction() {
         $products = new Products();
         $this -> view -> products = $products -> findByLimit(6);
         $posts = new Posts();
         $this -> view -> posts = $posts -> findByLimit(4);
         $this -> view -> titleForLayout = "Trang chủ - ".DEFAULT_NAME;
         $categories =  new ProductCategories();
         $result = $categories->getMenuToTree();

    echo "<pre>";
   print_r($result);exit;
    }

}