Added basic API endpoints (#258)

src/API/HealthcheckController.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\API;
+
+use FOS\RestBundle\Controller\Annotations as Rest;
+use FOS\RestBundle\View\View;
+use FOS\RestBundle\View\ViewHandlerInterface;
+use Swagger\Annotations as SWG;
+use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+
+class HealthcheckController extends Controller
+{
+    /**
+     * @var ViewHandlerInterface
+     */
+    protected $viewHandler;
+
+    /**
+     * @param ViewHandlerInterface $viewHandler
+     */
+    public function __construct(ViewHandlerInterface $viewHandler)
+    {
+        $this->viewHandler = $viewHandler;
+    }
+
+    /**
+     * @SWG\Response(
+     *     response=200,
+     *     description="A simple route that returns a 'pong', which you can use for testing the API",
+     * )
+     *
+     * @Rest\Get(path="/ping")
+     */
+    public function pingAction()
+    {
+        $view = new View(['message' => 'pong'], 200);
+
+        return $this->viewHandler->handle($view);
+    }
+}