Add a link to the python-coincidence contributing guide.

domdfcoding · domdfcoding · commit b36fa90dd41a · 2021-05-07T22:41:57.000+01:00
diff --git a/doc-source/index.rst b/doc-source/index.rst
@@ -146,6 +146,7 @@ Contents
 	:github:
 	:pypi: importcheck
 
+	Contributing Guide <https://contributing-to-coincidence.readthedocs.io/en/latest/>
 
 .. start links
 
