Undefined method 'cache_sweeper'

I am trying to set up some caching on my site and I am having trouble getting the cache utilizer running. I have followed Railscast , but when I try to load the model page I get an error. Here's what I've done so far:

1.) Added the app / sweepers directory and put the basic sweep in it:

class TeamMemberSweeper < ActionController::Caching::Sweeper
  observe TeamMember

  def after_create(team_member)
    expire_nav_menus
  end

  def after_destroy(team_member)
    expire_nav_menus
  end

  private

  def expire_nav_menus(athlete_id)
    expire_fragment(...)
  end
end

      

        
        
        
      

    

2.) Add the following TeamMember model:

cache_sweeper :team_member_sweeper, :only => [:create, :destroy]

      

        
        
        
      

    

3.) Added the following line to config / environment.rb and restarted my server:

config.load_paths += %W( #{RAILS_ROOT}/app/sweepers )

      

        
        
        
      

    

At this point, when I access the TeamMember model, I get the following error:

undefined method `cache_sweeper' for #<Class:0x23128cc>

      

        
        
        
      

    

What am I missing to get this to work?