If you don't have a RubyMotion app yet, generate one.
$ motion create myapp
$ cd myapp
You'll need to create a Gemfile. Here we're using bubblewrap.
Then, set up your Rakefile to require your bundled gems at compile time.
Add this to the top of the file, right beneath the line
Next, install your dependencies:
$ bundle install
Now you can just compile your app as normal.