Get rid of the Mongoid translation missing errors (Mongoid 4.0 & Rails 4.0)

If you are using Mongoid with an internationalised application, you will find that Mongoid tries to translate some errors. Since the major part of these errors are useful only for developers you may want to use english instead of translating them.

To fix this, you need to change your application.rb file, adding:

# Configure fallbacks for mongoid errors:
require "i18n/backend/fallbacks"
I18n::Backend::Simple.send(:include, I18n::Backend::Fallbacks)
config.i18n.fallbacks = {'es' => 'en'}

Then you will need to restart your server. Now you should get:

:)