Link to GitHub project from about page

mutalyzer/website/templates/about.html

@@ -50,6 +50,26 @@ please mention
   link</a>) when referring to these pages.
 </p>
 
+<h2>Open Source</h2>
+
+<p>
+Mutalyzer is Open Source and available under
+the <a href="http://www.gnu.org/licenses/agpl-3.0.html">GNU Affero General
+Public License</a>. Please <a href="mailto:mutalyzer@humgen.nl">contact the
+authors</a> if you want to discuss custom licensing.
+</p>
+
+<p>
+Contributions to Mutalyzer are very welcome! They can be feature requests, bug
+reports, bug fixes, unit tests, documentation updates, or anything els you may
+come up with.
+</p>
+
+<p>
+Development of Mutalyzer happens on
+GitHub: <a href="https://github.com/mutalyzer/mutalyzer">github.com/mutalyzer/mutalyzer</a>
+</p>
+
 <h2>Sponsors</h2>
 
 <p>