[CORD-2938] Moving convenience methods in the synchronizer containers

Change-Id: I8f06c238294b3e77badbef3e84a959561274204c
diff --git a/xos/synchronizer/models/convenience/vrouterapp.py b/xos/synchronizer/models/convenience/vrouterapp.py
new file mode 100644
index 0000000..3dafde2
--- /dev/null
+++ b/xos/synchronizer/models/convenience/vrouterapp.py
@@ -0,0 +1,33 @@
+
+# Copyright 2017-present Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import json
+from xosapi.orm import ORMWrapper, register_convenience_wrapper
+
+class ORMWrapperVRouterApp(ORMWrapper):
+    @property
+    def interfaces(self):
+        app_interfaces = []
+        devices = self.stub.VRouterDevice.objects.filter(vrouter_service_id=self.vrouter_service.id)
+        for device in devices:
+            ports = self.stub.VRouterPort.objects.filter(vrouter_device_id=device.id)
+            for port in ports:
+                interfaces = self.stub.VRouterInterface.objects.filter(vrouter_port_id=port.id)
+                for iface in interfaces:
+                    app_interfaces.append(iface.name)
+        return app_interfaces
+
+register_convenience_wrapper("VRouterApp", ORMWrapperVRouterApp)