Update open source view

resources/views/site/opensource.blade.php

@@ -6,4 +6,7 @@
     <h3 class="font-weight-bold">Open Source</h3>
   </div>
   <hr>
+  <section>
+    <p class="lead">The software that powers this website is called <a href="https://pixelfed.org">PixelFed</a> and anyone can <a href="https://github.com/dansup/pixelfed">download</a> the source code and run their own instance!</p>
+  </section>
 @endsection