I recently make a decision to translate my tiny rails app with I18n gem as it described here.
While a testing, as it expected, I got a error messages from activerecord and devise:
translation missing: ru.devise.failure.user.not_found_in_database
translation missing: ru.activerecord.errors.models.user.attributes.name.taken
At this moment I know only one way to set up massages with custom locale - simply copy en.yml file which contains messages into my custom ru.yml, but it's weird way.
Maybe I missed something?
Cheers!
You can use the default option (related question)
I also advise you to look into the rails-18n gem for common translations
Devise provide common translations on their wiki
You can also set up a fallback locale to avoid missing translations (related question)