In Bundler:

gem "uikit-on-rails"

And then execute:

bundle

Or install it yourself as::

gem install uikit-in-rails

Append the following line to your app/assets/stylesheets/application.css file:

/*= require uikit */

If you're planning on using Sass, then you'll want to rename application.css to application.sass. That file should then look like:

@import "uikit"

Append the following line to your app/assets/javascripts/application.js file:

//= require uikit