NoBrainer: error using default_scope in subclass

default-scope-on-subclass-test.rb

require 'nobrainer'

NoBrainer.configure do |config|
  config.app_name = "default-scope-on-subclass-test"
end

class Thing
  include NoBrainer::Document
end

class Subthing < Thing
  include NoBrainer::Document
  default_scope { order_by(:id) }
end

# /var/lib/gems/2.1.0/gems/nobrainer-0.20.0/lib/no_brainer/document/criteria.rb:46:in `default_scope': store_in() must be called on the parent class (RuntimeError)
#        from test.rb:13:in `<class:Subthing>'
#        from test.rb:11:in `<main>'