Add ability to specify ShibURLScheme

Change-Id: Ide373221a110c2e0f92f1d53fbbedba640f1781b
diff --git a/README.rst b/README.rst
index 3fde09f..bf5ceeb 100644
--- a/README.rst
+++ b/README.rst
@@ -321,6 +321,7 @@
           federation_driver: keystone.contrib.federation.backends.sql.Federation
           trusted_dashboard:
             - http://${_param:proxy_vip_address_public}/horizon/auth/websso/
+          shib_url_scheme: https
     apache:
       server:
         pkgs: