Add ceph backend option to report discard support
diff --git a/README.rst b/README.rst
index 73f684b..10c3c73 100644
--- a/README.rst
+++ b/README.rst
@@ -355,6 +355,7 @@
             user: cinder
             secret_uuid: da74ccb7-aa59-1721-a172-0006b1aa4e3e
             client_cinder_key: AQDOavlU6BsSJhAAnpFR906mvdgdfRqLHwu0Uw==
+            report_discard_supported: True
 
 http://ceph.com/docs/master/rbd/rbd-openstack/