ejemplo active admin through

gistfile1.txt

class Brand < ActiveRecord::Base
  has_many :car_models
end

class CarModel < ActiveRecord::Base
  has_many :production_years
  belongs_to :brand
end

class ProductionYear < ActiveRecord::Base
   belongs_to :car_model
   has_one :brand, :through => :car_model
end


ActiveAdmin.register ProductionYear do
  filter :brand, :as => :check_boxes, :collection => proc { Brand.all }
end