```ruby
Rails.application.routes.draw do
  resources :expanded_test_ads
  resources :ad_groups
  resources :campaigns
  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
end
```

Configure to route to controllers in API module
user
```ruby
Rails.application.routes.draw do
  constraints subdomain: 'api' do
    scope module: 'api' do
      namespace :v1 do
        resources :expanded_test_ads
        resources :ad_groups
        resources :campaigns
      end
    end
  end
end
```
assistant