add a link to the contributors graph on GH

Author: ivanov

README.rst

@@ -262,7 +262,7 @@ Known issues:
 ----------------------------
 Thanks and Bug Participation
 ----------------------------
-Here's a brief acknowledgment of the folks who have graciously pitched in. If
+Here's a brief acknowledgment of the `folks who have graciously pitched in`_. If
 you've been missed, don't hesitate to contact me, or better yet, submit a
 pull request with your attribution.
 
@@ -322,7 +322,7 @@ Similar Projects
 .. _ipyqtmacvim: https://github.com/jkitzes/ipyqtmacvim/
 .. _tslime_ipython: https://github.com/eldridgejm/tslime_ipython
 .. _vipy: https://github.com/johndgiese/vipy
-
+.. _folks who have graciously pitched in: https://github.com/ivanov/vim-ipython/graphs/contributors
 
 Bottom Line
 -----------