Simple, beautiful error messages for Rails. Err_supply unpacks and rekeys the standard Rails error hash to make applying error messages to your views dead simple. Even better, because the library cures Rails' brain-damaged way of recording errors from nested resources/attributes, err_supply works with both simple and complex forms.
Gemfile gem 'err_supply', '~> 0.1.3'
install gem install err_supply -v 0.1.3