Add README on how to add auth for Haproxy

Related-Prod: PROD-23434
Change-Id: If68180e0e4c35a520018cc0447fcb707a2c0741e
diff --git a/README.rst b/README.rst
index 503c2ca..3d3d21d 100644
--- a/README.rst
+++ b/README.rst
@@ -745,6 +745,68 @@
         tune_sndbuf_client: ''
         tune_sndbuf_server: ''
 
+It is possible to setup basic Auth through Haproxy:
+
+.. code-block:: yaml
+
+  haproxy:
+    proxy:
+      userlist:
+        sample_userlist:
+          name: sample_users
+          groups:
+            - name: 'g1'
+          users:
+            - name: user1
+              password: r00tme
+              groups: [ 'g1' ]
+
+You can add users and passwords following three different ways:
+
+  #. Put to model insecure password and Haproxy will shadow
+     it in config file:
+
+  .. code-block:: yaml
+
+    users:
+      - name: user1
+        password: r00tme
+
+  #. Put to model insecure password and Haproxy will put it as
+     insecured in config file:
+
+  .. code-block:: yaml
+
+    users:
+      - name: user2
+        password: r00tme
+        insecure_password: True
+
+  #. Put to model shadowed password and Haproxy will put it in
+     config file:
+
+  .. code-block:: yaml
+
+    users:
+      - name: user3
+        password: '$6$wf0xxoXj$VqoqozsTPpeKZtw6c7gl2CYyEXfOccdif1ZmJwDT1AMKYp/.JUTZcDiZthai3xN9CzDQex9ZUOf3nFMbCm/Oe.'
+        shadow_password: False
+
+To enable Auth rules you need to add following data for your
+backend/frontend/listen setup, for example for ``listen``:
+
+.. code-block:: yaml
+
+  haproxy:
+    proxy:
+      listen:
+        sample_api:
+          acl:
+            auth_reg: "http_auth(sample_users)"
+          http_request:
+            - action: auth
+              condition: 'if !auth_reg'
+
 Read more
 =========