parametrize client restrictions

Change-Id: I9640cf46f71ede1e0d24bac0b0e3d37a2ac19de0
diff --git a/README.rst b/README.rst
index 08ba87f..b73a1ad 100644
--- a/README.rst
+++ b/README.rst
@@ -63,6 +63,14 @@
               enabled: true
               key: ssh_rsa
 
+Backup server without strict client restriction
+
+.. code-block:: yaml
+
+    cassandra:
+      backup:
+        restrict_clients: false
+
 Client restore from local backup:
 
 .. code-block:: yaml