add PetSet support

Change-Id: Id887162e539f74141926e81cc9b45e61a2dbc80b
diff --git a/README.rst b/README.rst
index e2be335..c81b3d7 100644
--- a/README.rst
+++ b/README.rst
@@ -430,6 +430,21 @@
                 mount: /certs
                 path: /etc/certs
 
+PetSet manifest
+---------------------
+
+.. code-block:: yaml
+
+  service:
+    memcached:
+      apiVersion: apps/v1alpha1
+      kind: PetSet
+      service_name: 'memcached'
+      container:
+        memcached:
+      ...
+
+
 Configmap
 ---------