Rails Model Concern: track which classes have included the Concern

gistfile1.rb

require 'active_support/concern'

module ChildTrackable
  extend ActiveSupport::Concern

  # keep track of what classes have included this concern:
  module Children
    extend self
    @included_in ||= []

    def add(klass)
      @included_in << klass
    end

    def included_in
      @included_in
    end
  end

  included do

    # track which classes have included this model concern
    Children.add self

  end

end

# access at:
ChildTrackable::Children.included_in