Ivan Zuzak wrote about it here. It’s actually a very cool idea. All you need is to create a new repo on GitHub, create an issue for the blog post you want to enable comment and set
If I were to enable comments on my blog, I would defenitely go this route. You already blog like a hacker, you should also comment like one.
I’ve also seen people using Discourse for their website’s comments. The downside is setting up a new VPS and install Discourse(an online discussion software) seems like overkill for this purpose. Also, Discourse is not exactly lightweight. In order to install Discourse, you need a VPS with minimum 1GB of RAM (at least that was when I last tried it). My VPS has mere 128MB of memory, not exactly a beasty machine. The reason I went with static blog is it’s very lightweight. Using Discourse kinda defeat the purpose now, doesn’t it?
If you don’t want to go through all the troubles, you can use Disqus instead.