Add link to GitHub repo csswg-drafts

Author: mrego

index.html

@@ -47,7 +47,7 @@ <h1>CSS Grid Layout Examples</h1>
                             <a class="list-group-item" href="http://dev.w3.org/csswg/css-grid/"><h4>Editor's Draft (ED)</h4></a>
                         </div>
                     </div>
-                    <div class="alert alert-info"><a href="http://www.w3.org/Search/Mail/Public/search?keywords=&hdr-1-name=subject&hdr-1-query=%5Bcss-grid%5D&index-grp=Public_FULL&index-type=t&type-index=www-style">Discussion at www-style mailing list</a></div>
+                    <div class="alert alert-info"><a href="https://github.com/w3c/csswg-drafts/issues?utf8=%E2%9C%93&q=is%3Aissue%20css-grid%20">Discussion at csswg-drafts GitHub repository</a><br><a href="http://www.w3.org/Search/Mail/Public/search?keywords=&hdr-1-name=subject&hdr-1-query=%5Bcss-grid%5D&index-grp=Public_FULL&index-type=t&type-index=www-style">Discussion at www-style mailing list</a></div>
                     <div class="panel panel-default">
                         <div class="panel-heading"><h3>Implementation</h3></div>
                         <table class="table">