parametrize client restrictions

Change-Id: I4c21f6190a5dcc9b70ff60143cceae94cdeb834a
diff --git a/README.rst b/README.rst
index eb74d17..8450bf9 100644
--- a/README.rst
+++ b/README.rst
@@ -721,6 +721,14 @@
               enabled: true
               key: ssh_rsa
 
+Backup server without strict client restriction
+
+.. code-block:: yaml
+
+    ceph:
+      backup:
+        restrict_clients: false
+
 Migration from Decapod to salt-formula-ceph
 --------------------------------------------