Update index.html to include opensource bookmark

static/instance/about.example/index.html

@@ -26,6 +26,11 @@
   <li>Lewd jokes.</li>
   <li>A bot where all posts are unlisted.</li>
 </ol>
+
+<h1 id="opensource">Open Source Software</h1>
+<p>Soapbox is free and open source (FOSS) software that runs atop a Pleroma server</p>
+<p>The Soapbox repository can be found at <a href="https://gitlab.com/soapbox-pub/soapbox-fe">Soapbox-fe</a></p>
+<p>The Pleroma server repository can be found at <a href="https://git.pleroma.social/pleroma/pleroma">Pleroma-be</a></p>
 </div>
 </body>
 </html>