```ruby
module NotifyUser
  class Engine < ::Rails::Engine
  	require 'active_model_serializers'
    require 'urbanairship'

    config.generators do |g|
      g.test_framework      :rspec,        :fixture => false
      g.fixture_replacement :factory_girl, :dir => 'spec/factories'
      g.assets false
      g.helper false
    end
  end
end
```

Add CSS to precompile, now it's not added to application.css by the installer
user
```ruby
module NotifyUser
  class Engine < ::Rails::Engine
  	require 'active_model_serializers'
    require 'urbanairship'

    config.generators do |g|
      g.test_framework      :rspec,        :fixture => false
      g.fixture_replacement :factory_girl, :dir => 'spec/factories'
      g.assets false
      g.helper false
    end

    Rails.application.config.assets.precompile += %w{ notify_user/notify_user.css }
  end
end
```
assistant