cloner to easily clone dependent repositories

The intent is to replace the devstack shell script with a python utility
which would be easy to reuse.

Change-Id: I3c8748e2544af80e72fdd0b2e3627b4fc2212c01
diff --git a/doc/source/index.rst b/doc/source/index.rst
index fcc0d45..abe8089 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -20,6 +20,7 @@
    reporters
    zuul
    client
+   cloner
    statsd
 
 Indices and tables