'monetize' test matcher works when testing against the model class as well as an instance of the model, and is agnostic about the actual values of the tested columns at runtime
raise an error if trying to create a monetized attribute with the same name as an existing attribute
Merge pull request #258 from RubyMoney/duplicate-attributes

raise an error if trying to create a monetized attribute with the same name as an existing attribute
Merge pull request #256 from RubyMoney/monetize-matcher

Improvements to `monetize` test matcher.
use HashWithIndifferentAccess instead of Hash for ActiveRecord::Base::monetized_attributes