Implement X.509 auth for MySQL and Panko

Related-PROD: PROD-22752

Change-Id: Ie81921548f67b0a6155d3101ee59eed845e95a58
diff --git a/README.rst b/README.rst
index 1cceabc..f1b324d 100644
--- a/README.rst
+++ b/README.rst
@@ -94,6 +94,28 @@
           fluentd:
             enabled: true
 
+Enable x509 and ssl communication between Panko and Galera cluster.
+---------------------
+By default communication between Panko and Galera is unsecure.
+
+panko:
+  server:
+    database:
+      x509:
+        enabled: True
+
+You able to set custom certificates in pillar:
+
+panko:
+  server:
+    database:
+      x509:
+        cacert: (certificate content)
+        cert: (certificate content)
+        key: (certificate content)
+
+You can read more about it here:
+    https://docs.openstack.org/security-guide/databases/database-access-control.html
 
 More information
 ================