fix: add disqus comment

Author: qiwihui

_config.yml

@@ -34,3 +34,6 @@ target-blank:
     rel: nofollow
 
 header_page_refs: ['about']
+
+disqus:
+  shortname: "pyweekly"

_includes/disqus_comments.html

@@ -0,0 +1,20 @@
+{%- if page.comments != false and jekyll.environment == "production" -%}
+
+  <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.disqus.shortname }}.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>
+{%- endif -%}