zammad/config/routes/online_notification.rb

Zammad::Application.routes.draw do
  api_path = Rails.configuration.api_path

  # groups
  match api_path + '/online_notifications',             :to => 'online_notifications#index',  :via => :get
  match api_path + '/online_notifications/:id',         :to => 'online_notifications#update', :via => :put

end