route アクション追加

ルーティング

Rails.application.routes.draw do
  resources :forms, only: [:show], param: :app_id do
    get 'fetch_kintone', on: :member
    get 'post_to_kintone', on: :collection
  end
end

確認

Prefix Verb URI Pattern                            Controller#Action
fetch_kintone_form GET  /forms/:app_id/fetch_kintone(.:format) forms#fetch_kintone
post_to_kintone_forms GET  /forms/post_to_kintone(.:format)       forms#post_to_kintone
                 form GET  /forms/:app_id(.:format)               forms#show