def list_order(f, attribute, options)
      if is_association?(f, attribute) && !options[:collection]
        begin
          options[:collection] = to_class(attribute).for_fae_index
        rescue NameError
          raise "Fae::MissingCollection: `#{attribute}` isn't an orderable class, define your order using the `collection` option."
        end
      end
    end
def list_order(f, attribute, options)
      if is_association?(f, attribute) && !options[:collection]
        begin
          options[:collection] = to_class(attribute).for_fae_index
        rescue NameError
          raise "Fae::MissingCollection: `#{attribute}` isn't an orderable class, define your order using the `collection` option."
        end
      end
    end
sets collection to class.for_fae_index if not defined