create generic data transformer with get an object by id, and add test

for CalendarType

src/Bundle/ChillMainBundle/Form/DataTransformer/IdToUsersDataTransformer.php

@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Chill\MainBundle\Form\DataTransformer;
+
+use Chill\MainBundle\Repository\UserRepository;
+
+class IdToUsersDataTransformer extends IdToEntityDataTransformer
+{
+    public function __construct(UserRepository $repository)
+    {
+        parent::__construct($repository, true);
+    }
+}