link the Installation Section where people look for contributing

CONTRIBUTING.rst

@@ -21,3 +21,11 @@ For pull requests, keep this in mind
 - Describe your change in CHANGES.rst
 
 - Add yourself to the docs/credits.rst
+
+Development Setup
+-----------------
+
+If you would like to setup icalendar to
+contribute changes, the `Installation Section
+<https://icalendar.readthedocs.io/en/latest/install.html>`_
+should help you further.