add docker_image_name to VSGService Tosca

Change-Id: I60278f9d10d0afdb80d110de96eaf2d2beea403e
diff --git a/xos/tosca/custom_types/xos.m4 b/xos/tosca/custom_types/xos.m4
index d84672e..3b34216 100644
--- a/xos/tosca/custom_types/xos.m4
+++ b/xos/tosca/custom_types/xos.m4
@@ -385,6 +385,9 @@
             node_label:
                 type: string
                 required: false
+            docker_image_name:
+                type: string
+                required: false
 
     tosca.nodes.VBNGService:
         derived_from: tosca.nodes.Root
diff --git a/xos/tosca/custom_types/xos.yaml b/xos/tosca/custom_types/xos.yaml
index b2adcb5..cedfbeb 100644
--- a/xos/tosca/custom_types/xos.yaml
+++ b/xos/tosca/custom_types/xos.yaml
@@ -661,6 +661,9 @@
             node_label:
                 type: string
                 required: false
+            docker_image_name:
+                type: string
+                required: false
 
     tosca.nodes.VBNGService:
         derived_from: tosca.nodes.Root