adapt UI and controller for Person without centers

src/Bundle/ChillPersonBundle/Controller/PersonController.php

@@ -230,13 +230,16 @@ final class PersonController extends AbstractController
      */
     public function newAction(Request $request)
     {
-        $defaultCenter = $this->security
-                        ->getUser()
-                        ->getGroupCenters()[0]
-                        ->getCenter();
+        $person = new Person();
 
-        $person = (new Person(new \DateTime('now')))
-                ->setCenter($defaultCenter);
+        if (1 === count($this->security->getUser()
+                ->getGroupCenters())) {
+            $person->setCenter(
+                $this->security->getUser()
+                    ->getGroupCenters()[0]
+                    ->getCenter()
+            );
+        }
 
         $form = $this->createForm(CreationPersonType::class, $person, [
             'validation_groups' => ['create']