Shopify/batman — pull request #693 by conraddecker (2013-04-26 15:34:46+00:00)
Title: Update Model#create to set default callback argument to empty object.

Model#create is currently setting attrs to a blank object when called with no callback.
I adjusted the method definition to set the default `callback` argument to a blank object.

See: https://github.com/Shopify/batman/issues/689