add CONTRIBUTING.rst

This was copied from keystone; the only change was the link to launchpad.

Change-Id: I39efde532abadbba9062d05207368e96c3486bc4
Closes-Bug: 1335965

1 files changed, 2 insertions, 0 deletions

diff --git a/README.rst b/README.rst
index 308de85..28781c5 100644
--- a/README.rst
+++ b/README.rst
@@ -18,3 +18,5 @@ Bugs and feature requests are tracked on Launchpad at:
 For any other information, refer to the parent project, Keystone:
 
     https://github.com/openstack/keystone
+
+For information on contributing, see ``CONTRIBUTING.rst``.