Update jms_serializer.yaml

Create object if it no longer exists

Author: ychadwick

src/Resources/config/cms/jms_serializer.yaml

@@ -1,9 +1,12 @@
 jms_serializer:
+    object_constructors:
+        doctrine:
+            fallback_strategy: fallback
     metadata:
         directories:
             NetworkingSonataMediaBundle:
                 namespace_prefix: "Sonata\\MediaBundle"
                 path: "@NetworkingInitCmsBundle/Resources/config/serializer"
             app:
                 namespace_prefix: "App"
-                path: "%kernel.project_dir%/config/serializer"
+                path: "%kernel.project_dir%/config/serializer"