class Middleman::ConfigExtension

def after_configuration
  context = self
  self.class.exposed_to_config.each do |k, v|
    ::Middleman::CoreExtensions::Collections::StepContext.add_to_context(k) do |*args, &b|
      r = context.method(:"__original_#{v}").call(*args, &b)
      descriptors << r if r.respond_to?(:execute_descriptor)
    end
  end
end