Update footer.html

Author: daattali

_includes/footer.html

@@ -28,10 +28,12 @@
       {% endif%}
       </p>
       <!-- Please don't remove this, keep my open source work credited :) -->
+      {% if site.remove-ads %}
       <p class="theme-by text-muted">
         Theme by
         <a href="https://beautifuljekyll.com">beautiful-jekyll</a>
       </p>
+      {% endif%}
       </div>
     </div>
   </div>