WebSSO support for Horizon

Change-Id: I47619663c107011a9dc30eba6bf554b7ce63d69a
diff --git a/README.rst b/README.rst
index a486264..18da802 100644
--- a/README.rst
+++ b/README.rst
@@ -352,6 +352,20 @@
               address: https://github.com/openstack/horizon.git
               rev: stable/juno
 
+Enable WebSSO feature
+
+.. code-block:: yaml
+
+    horizon:
+      server:
+        enabled: true
+        websso:
+          login_url: "WEBROOT + 'auth/login/'"
+          logout_url: "WEBROOT + 'auth/logout/'"
+          websso_choices:
+            - saml2
+            - oidc
+
 Read more
 =========