Optionally, if you have a Disqus account, you can tell Jekyll to use it to show a comments section below each post. To enable it, add the following lines to your Jekyll site:
disqus:
shortname: my_disqus_shortname
You can find out more about Disqus’ shortnames here.
Comments are enabled by default and will only appear in production, i.e., JEKYLL_ENV=production. If you don’t want to display comments for a particular post you can disable them by adding comments: false to that post’s YAML Front Matter.