Routing setup you must do manually if you haven't yet:

Rails.application.routes.draw do
  resources :meetings, only: [:index, :show, :create, :destroy] do
    resources :meeting_attendees, as: :attendees, path: :attendees, only: [:index, :show]
  end
end

Examples:

If you generated controllers with room as parent resource by –parent option, setup routes like this:

Rails.application.routes.draw do
  resources :rooms do
    resources :meetings, only: [:index, :show, :create, :destroy] do
      resources :meeting_attendees, as: :attendees, path: :attendees, only: [:index, :show]
    end
  end
end

If you generated controllers for Rails API with api as namespace by –namespace option, setup routes like this:

Rails.application.routes.draw do
  namespace :api do
    scope :"v1" do
      resources :meetings, defaults: { format: :json }, only: [:index, :show, :create, :destroy] do
        resources :meeting_attendees, as: :attendees, path: :attendees, only: [:index, :show, :create, :destroy]
      end
    end
  end
end