hierarchy.rb

ActionDispatch::Routing::PolymorphicRoutes.module_eval do
  def polymorphic_url_with_hierarchy(record, options={})
    record = record.hierarchy if record.respond_to?(:hierarchy)
    polymorphic_url_without_hierarchy(record, options)
  end
  alias_method_chain :polymorphic_url, :hierarchy
end

ActionView::Helpers::FormHelper.module_eval do
  def form_for_with_hierarchy(object, *args, &block)
    object = object.hierarchy if object.respond_to?(:hierarchy)
    form_for_without_hierarchy(object, *args, &block)
  end
  alias_method_chain :form_for, :hierarchy
end