Add disqus comment to this theme.

Signed-off-by: Tao He <sighingnow@gmail.com>

README.md

@@ -100,6 +100,14 @@ tracker:
   application_insights: "<YOUR APPLICATION INSIGHTS CONNECTION STRING>"
 ```
 
+## Disqus comments
+
+[Disqus](https://disqus.com/) comments can be enabled by adding the following configuration in `_config.yaml`:
+
+```yaml
+disqushandler: "<YOUR DISQUS SHORTNAME>"
+```
+
 ## Extra StyleSheet or Javascript elements
 
 You can add extra CSS or JavaScript references using configuration collections:

_config.yml

@@ -38,10 +38,13 @@ kramdown:
 
 syntax_highlighter_style: colorful
 
-markdown_ext:     markdown,mkdown,mkdn,mkd,md
+markdown_ext:             markdown,mkdown,mkdn,mkd,md
 
 # Permalinks
-permalink:        /:categories/:year-:month-:day-:title:output_ext
+permalink:                /:categories/:year-:month-:day-:title:output_ext
+
+# Disqus comments
+# disqushandler:            sighingnow
 
 exclude:
   - _drafts

_includes/body.html

@@ -19,6 +19,10 @@ <h1 id="{{ page.id }}">{{ site.title | escape }}</h1>
                     {% endif %}
 
                     {{ content }}
+
+                    {%- if jekyll.environment != 'dev' and site.disqushandler -%}
+                        {%- include disqus.html -%}
+                    {%- endif -%}
                 </section>
             </div>
 

_includes/disqus.html

@@ -0,0 +1,19 @@
+{% if site.disqushandler && page.disqus != false %}
+  <br/><br/><h3>Comments:</h3>
+  <div id="disqus_thread"></div>
+  <script>
+    var disqus_config = function () {
+      this.page.url = '{{ page.url | absolute_url }}';
+      this.page.identifier = '{{ page.url | absolute_url }}';
+    };
+
+    (function() {
+      var d = document, s = d.createElement('script');
+      s.src = 'https://{{ site.disqushandler }}.disqus.com/embed.js';
+      s.setAttribute('data-timestamp', +new Date());
+      (d.head || d.body).appendChild(s);
+    })();
+  </script>
+  <noscript>Please enable JavaScript to view the <a href="https://disqus.com/?ref_noscript" rel="nofollow">comments powered by Disqus.</a></noscript>
+  <a href="https://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a>
+{% endif %}