Update security.rst

Author: norbert-n

book/security.rst

@@ -189,6 +189,7 @@ example, if you use annotations, create something like this::
     // ...
 
     use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
+    use Symfony\Bundle\FrameworkBundle\Controller\Controller;
     use Symfony\Component\HttpFoundation\Response;
 
     class DefaultController extends Controller