Change extensions list type

This patch changes type of extensions pillar to dictionary

Change-Id: Ia8b155766daa111973e90bd59aacaec6a3778506
Related-PROD: PROD-14689
diff --git a/README.rst b/README.rst
index 4a5787a..3b161e5 100644
--- a/README.rst
+++ b/README.rst
@@ -953,8 +953,14 @@
       server:
         backend:
           extension:
-            - dns
-            - qos
+            dns:
+              enabled: True
+              host: 127.0.0.1
+              port: 9001
+              protocol: http
+              ....
+            qos
+              enabled: True
 
 
 Documentation and Bugs