Added Doctrine Entities.

src/Controller/HomepageController.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Controller;
+
+
+use App\Entity\Attachment;
+use App\Entity\AttachmentType;
+use App\Entity\Category;
+use App\Entity\StructuralDBElement;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Annotation\Route;
+
+class HomepageController extends AbstractController
+{
+    /**
+     * @Route("/")
+     */
+    function homepage()
+    {
+        $repo = $this->getDoctrine()->getRepository(Category::class);
+
+        /** @var StructuralDBElement  $attachment */
+        $attachment = $repo->find(1);
+
+        dump($attachment, $attachment->getSubelements(false)->toArray());
+        $response = "";
+        return $this->render('base.html.twig');
+    }
+}