Added option for specifying proxy server

Change-Id: I950d0c51ded4e956fe5f574e7c6cf3036c9200f3
Closes-bug: PROD-20677
diff --git a/README.rst b/README.rst
index 7ed259d..f53682f 100644
--- a/README.rst
+++ b/README.rst
@@ -15,6 +15,11 @@
           enabled: true
           mirrors:
             target01:
+              http_proxy : "url"
+              https_proxy: "url"
+              ftp_proxy: "url"
+              rsync_proxy: "url"
+              no_proxy: ['val1', 'val2']
               force: False
               lock_target: True
               extra_flags: [ '--verbose', '--progress', '--nosource', '--no-check-gpg', '--rsync-extra=none' ]