Documentation update, audit cadf support

Change-Id: Icd8b8e9d6a1fc10bd2bd9514cee00234c18b7e57
diff --git a/README.rst b/README.rst
index 76d1f6c..da70b08 100644
--- a/README.rst
+++ b/README.rst
@@ -67,6 +67,8 @@
             tenant: service
         metadata:
           password: password
+        audit:
+          enabled: false
 
 
 Nova services from custom package repository
@@ -101,6 +103,20 @@
       ....
 
 
+Enable auditing filter, ie: CADF
+
+.. code-block:: yaml
+
+    nova:
+      controller:
+        autidt:
+          enabled: true
+      ....
+          filter_factory: 'keystonemiddleware.audit:filter_factory'
+          map_file: '/etc/pycadf/nova_api_audit_map.conf'
+      ....
+
+
 Compute nodes
 -------------