Unhradcoding compute.user.groups for nova. Upgrade related

Change-Id: Ia7c9c456f47123ed48a6fe19e2a8e57bb99b5f0c
diff --git a/README.rst b/README.rst
index 5b601e4..9c04211 100644
--- a/README.rst
+++ b/README.rst
@@ -208,6 +208,18 @@
           max_files: 4096
           max_processes: 4096
 
+Group membership for user nova (upgrade related)
+
+.. code-block:: yaml
+
+    nova:
+      compute:
+        enabled: true
+        ...
+        user:
+          groups:
+          - libvirt
+
 Nova services on compute node with OpenContrail
 
 .. code-block:: yaml