Does it work with `github-pages` gem?

I can't get this working with the `github-pages` gem, which is just a gem that pins jekyll and some extra dependencies to match the versions running on GitHub Pages.

My `Gemfile` looks like this:

``` ruby
source 'https://rubygems.org'

gem 'jekyll-compose'
gem 'github-pages'
```

Using bundler but the new commands from compose are not being installed. What am I missing?
