Make Translation.available_locales select distinct values.
Make Translation.available_locales select distinct values.

Before:
> Translation.available_locales
SELECT DISTINCT `translations`.* FROM `translations`

After:
> Translation.distinct.pluck(:locale).map(&:to_sym)
SELECT DISTINCT `translations`.`locale` FROM `translations`

fatbeard2/i18n-active_record,alterego-labs/i18n-active_record,uken/i18n-active_record,svenfuchs/i18n-active_record,lcowell/i18n-active_record,shutl/i18n-active_record,svenfuchs/i18n-active_record,kerglis/i18n-active_record