add support for comments on any page

_layouts/post.html

@@ -41,8 +41,10 @@ layout: default
   </div>
 </div>
 
-<div class="row blog-comments">
+{% if page.comments %}
+<div class="row disqus-comments">
   <div class="col-lg-8 col-lg-offset-2 col-md-10 col-md-offset-1">
     {% include disqus.html %}
   </div>
 </div>
+{% endif %}