Add the following to your site’s Gemfile

gem 'jemoji'

And add the following to your site’s _config.yml

plugins:
  - jemoji

If you are using a Jekyll version less than 3.5.0, use the gems key instead of plugins.

In any page or post, use emoji as you would normally, e.g.

I give this plugin two :+1:!

A handy emoji cheat sheet