неопределенный метод `write_inheritable_attribute' для ContactsController:Class

Я обновил свою версию Rails с 3.2.13 до Rails 4.2.6. В старой версии они использовали плагин map_fields, где в моем контроллере контактов:

class ContactsController < ApplicationController
  require 'map_fields'
  map_fields :mapper, ['First Name','Last Name', 'Email', 'Notes'], :file_field => :file, :params => [:contact]

  def create
    @user = User.find(params[:user_id])
    @contact = @user.contacts.create(contact_params)
    respond_to do |format|
      if @contact.save
        format.json { render :json => { :notice => 'Contact was successfully created!',:redirect => user_contacts_url} }
        format.html { redirect_to(user_contacts_url(@user), :notice => 'Contact was successfully created!', :type => 'success') }
       else
        format.json { render :json => {:redirect => false} }
        format.html { render :action => "edit" }
      end
    end
  end
  def import
    @contact = Contact.new 
  end
    def mapper
    @contact = Contact.new(params[:contact])
    count = 0

    if fields_mapped?
      mapped_fields.each do |row|
        params[:contact] = {"user_id" => @current_user.id, "firstname" => row[0], "lastname" => row[1], "notes" => row[3], "email" => row[2].try(:strip)}
        contact = Contact.new(params[:contact])

        if contact.save
          count = count + 1
        end
      end

      if count > 0
        flash[:notice] = "#{count} Contact(s) created"
        redirect_to :action => :index
      else 
        flash[:notice] = "No contact was created..." 
        redirect_to :action => :index
      end

    else
      @best_row = @rows[1]
      render
    end

    rescue MapFields::InconsistentStateError
      flash[:error] = 'Please try again'
      redirect_to :action => :import
    rescue MapFields::MissingFileContentsError
      flash[:error] = 'Please upload a file'
      redirect_to :action => :import
  end

end

когда я запускаю код, я получаю ошибку

ActionController::RoutingError - undefined method `write_inheritable_attribute' for ContactsController:Class:
actionpack (4.2.6) lib/action_dispatch/routing/route_set.rb:63:in `rescue in controller'
actionpack (4.2.6) lib/action_dispatch/routing/route_set.rb:58:in `controller'
actionpack (4.2.6) lib/action_dispatch/routing/route_set.rb:39:in `serve'
actionpack (4.2.6) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.6) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.6) lib/action_dispatch/routing/route_set.rb:817:in `call'
meta_request (0.4.0) lib/meta_request/middlewares/app_request_handler.rb:13:in `call'
meta_request (0.4.0) lib/meta_request/middlewares/meta_request_handler.rb:13:in `call'
warden (1.2.6) lib/warden/manager.rb:35:in `block in call'
warden (1.2.6) lib/warden/manager.rb:34:in `call'
client_side_validations (4.2.5) lib/client_side_validations/middleware.rb:15:in `call'
rack (1.6.4) lib/rack/etag.rb:24:in `call'
rack (1.6.4) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.4) lib/rack/head.rb:13:in `call'
remotipart (1.2.1) lib/remotipart/middleware.rb:27:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.6) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.6) lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.6) lib/active_support/callbacks.rb:88:in `__run_callbacks__'
activesupport (4.2.6) lib/active_support/callbacks.rb:778:in `_run_call_callbacks'
activesupport (4.2.6) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.6) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
rails-dev-tweaks (1.2.0) lib/rails_dev_tweaks/granular_autoload/middleware.rb:36:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
airbrake (4.3.8) lib/airbrake/rails/middleware.rb:13:in `call'
better_errors (2.1.1) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:57:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
rack-contrib (1.4.0) lib/rack/contrib/response_headers.rb:17:in `call'
meta_request (0.4.0) lib/meta_request/middlewares/headers.rb:16:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.6) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.6) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.6) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.6) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.6) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.6) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.6) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.6) lib/action_dispatch/middleware/static.rb:120:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
airbrake (4.3.8) lib/airbrake/user_informer.rb:16:in `_call'
airbrake (4.3.8) lib/airbrake/user_informer.rb:12:in `call'
railties (4.2.6) lib/rails/engine.rb:518:in `call'
railties (4.2.6) lib/rails/application.rb:165:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
thin (1.5.1) lib/thin/connection.rb:81:in `block in pre_process'
thin (1.5.1) lib/thin/connection.rb:79:in `pre_process'
thin (1.5.1) lib/thin/connection.rb:54:in `process'
thin (1.5.1) lib/thin/connection.rb:39:in `receive_data'
eventmachine (1.0.9.1) lib/eventmachine.rb:193:in `run'
thin (1.5.1) lib/thin/backends/base.rb:63:in `start'
thin (1.5.1) lib/thin/server.rb:159:in `start'
rack (1.6.4) lib/rack/handler/thin.rb:19:in `run'
rack (1.6.4) lib/rack/server.rb:286:in `start'
railties (4.2.6) lib/rails/commands/server.rb:80:in `start'
railties (4.2.6) lib/rails/commands/commands_tasks.rb:80:in `block in server'
railties (4.2.6) lib/rails/commands/commands_tasks.rb:75:in `server'
railties (4.2.6) lib/rails/commands/commands_tasks.rb:39:in `run_command!'
railties (4.2.6) lib/rails/commands.rb:17:in `<top (required)>'
bin/rails:4:in `<main>'

Это мой файл route.rb:

Htm::Application.routes.draw do
  .......................other routes......
  resources :contacts do
      post :import_remote,  :on => :collection
      get :import_remote,   :on => :collection
      collection  do
        post    :mapper
        get     :import
        post    :destroy_multiple
        delete  :destroy_all
      end
    end
end

Я выполнил те же шаги, которые вы указали в проблеме 1, но я получаю эту ошибку . Пожалуйста помоги.