You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: omniauth_callbacks_controller.rb
    path of file: ./repos/huginn/app/controllers
    
    the code of the file until where you have to start completion: class OmniauthCallbacksController < Devise::OmniauthCallbacksController
  def action
    
  def action_missing(name)
    case name.to_sym
    when *Devise.omniauth_providers
      service = current_user.services.initialize_or_update_via_omniauth(request.env['omniauth.auth'])
      if service && service.save
        redirect_to services_path, notice: "The service was successfully created."
      else
        redirect_to services_path, error: "Error creating the service."
      end