Add a link to the GitHub repository

Author: mskopp

pages-layout/_layouts/default.html

@@ -31,8 +31,11 @@ <h1>
                 contractual agreements. <br> This description is published by <a
                     href="https://riege.com">Riege Software</a> under <a href="{{ "
                     /assets/files/license.txt?v=" | append: site.github.build_revision | relative_url }}">UPL
-                    license</a>. <a href="https://www.riege.com/imprint/">Imprint</a> <a
-                    href="https://www.riege.com/privacy/">Privacy</a>
+                    license</a>. <a href="https://www.riege.com/imprint/">Imprint</a>. <a
+                    href="https://www.riege.com/privacy/">Privacy</a>. <br> {% if
+                site.github.is_project_page %} <a
+                    href="{{ site.github.repository_url }}"><small>View
+                        project on GitHub</small></a> {% endif %}
             </p>
         </div>
     </div>