disqus: ensure same discussion is used regardless of query params in URL

_includes/disqus.html

@@ -3,6 +3,9 @@
 	<div id="disqus_thread"></div>
 	<script type="text/javascript">
 	    var disqus_shortname = '{{ site.disqus }}';
+	    // ensure that pages with query string get the same discussion
+            var url_parts = window.location.href.split("?");
+            var disqus_url = url_parts[0];	    
 	    (function() {
 	        var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true;
 	        dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js';