setting-rails3-engine-root.rb

# instead of setting all paths individually, you set all of them relative to
# another root, say my_gem/lib/rails/engine this way

if defined?(Rails)

  module MyGem 
    class Engine < Rails::Engine

      paths.path = MyGem.engine_dir

      p paths.app.to_a             #=> MyGem.engine_dir + '/app'
      p paths.app.controllers.to_a #=> MyGem.engine_dir + '/app/controllers'

    end
  end

end