add api

config/routes.rb

@@ -1,5 +1,6 @@
 Rails.application.routes.draw do
   devise_for :admin_users, ActiveAdmin::Devise.config
   ActiveAdmin.routes(self)
+  resources :messages, controller: 'messages'
   # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
 end