enable prometheus metrics in felix

Calico Felix can listen on port 9091 (configurable) and export
prometheus metrics here.

Change-Id: I927d9ee952c4b1aacae80c7e0f9b6adbf90e8a9c
diff --git a/README.rst b/README.rst
index 98785ed..16f967b 100644
--- a/README.rst
+++ b/README.rst
@@ -193,8 +193,6 @@
             kubelet: 7bN5hJ9JD4fKjnFTkUKsvVNfuyEddw3r
           version: v1.2.4
 
-
-
 Kubernetes with OpenContrail network plugin
 ------------------------------------------------
 
@@ -354,6 +352,20 @@
             ssl:
               enabled: true
 
+Enable Prometheus metrics in Felix
+
+.. code-block:: yaml
+
+    kubernetes:
+      pool:
+        network:
+          prometheus:
+            enabled: true
+      master:
+        network:
+          prometheus:
+            enabled: true
+
 Post deployment configuration
 
 .. code-block:: bash