setup batman.js and rails-api

batman-rails

~~~
# Gemfile
gem 'rails-api'

gem 'active_model_serializers', :github => 'rails-api/active_model_serializers'
gem 'batman-rails', git: 'git://github.com/Shopify/batman-rails.git'
~~~

~~~
$ bundle
~~~

~~~
$ rails-api new app
~~~

~~~
$ mkdir -p app/assets/{images,javascripts,stylesheets}
$ mkdir -p lib/assets/{images,javascripts,stylesheets}
$ touch app/assets/javascripts/application.js
$ echo "//= app" > app/assets/javascripts/application.js
~~~

~~~
$ rails g batman:install
~~~