udpate readmin with audit support

Change-Id: I942f5bee81789cac8c842d9af0737f59569c6c06
diff --git a/README.rst b/README.rst
index 7dc6475..54e3480 100644
--- a/README.rst
+++ b/README.rst
@@ -261,6 +261,15 @@
           virtual_host: '/openstack'
           ha_queues: true
 
+Enable CADF audit notification
+
+.. code-block:: yaml
+
+    keystone:
+      server:
+        notification: true
+        notification_format: cadf
+
 
 Keystone client
 ---------------