It's working!

config/bundles.php

@@ -2,4 +2,5 @@
 
 return [
     Symfony\Bundle\FrameworkBundle\FrameworkBundle::class => ['all' => true],
+    Sensio\Bundle\FrameworkExtraBundle\SensioFrameworkExtraBundle::class => ['all' => true],
 ];

config/packages/sensio_framework_extra.yaml

@@ -0,0 +1,3 @@
+sensio_framework_extra:
+    router:
+        annotations: false

config/routes.yaml

@@ -1,3 +1,3 @@
 #index:
-#    path: /
-#    controller: App\Controller\DefaultController::index
+#     path: /
+#     controller: App\Controller\QuestionController::homepage

config/routes/annotations.yaml

@@ -0,0 +1,7 @@
+controllers:
+    resource: ../../src/Controller/
+    type: annotation
+
+kernel:
+    resource: ../../src/Kernel.php
+    type: annotation