Interesting, thanks.

Current Gemfile:

  # ...

  # i18n
  gem 'rails_locale_detection' # consider locale_setter
  gem 'rails-i18n', github: 'steakknife/rails-i18n'
  gem 'i18n_data', github: 'steakknife/i18n_data'
  gem 'countries_and_languages', require: 'countries_and_languages/rails'
  gem 'country_select' # for simple_form

  # tz
  gem 'tzinfo-data', '>= 1.2014.1'
  gem 'tzinfo'

  # symbols and images
  gem 'svg-flags-rails'

  # idn
  gem 'resolv-idn'   # resolv unicode patch
  gem 'idn-ruby'     # unicode IDNA domain resolution
  # ...

  # ...