add source link

index.html

@@ -34,6 +34,6 @@
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-  <div class="footer"><a href="https://mastodon.technology/@mdszy">mark</a> made this. <a href="https://liberapay.com/mdszy/">tips if you hate money</a></div>
+  <div class="footer"><a href="https://mastodon.technology/@mdszy">mark</a> made this. <a href="https://gitlab.com/mdszy/et">source code is here</a>. <a href="https://liberapay.com/mdszy/">tips if you hate money</a></div>
 </body>
 </html>