フォームのバリデーションとニコ連携の画面変更 (#090) (#355)

Reviewed-on: http://git.miteruzo.com/miteruzo/btrc-hub/pulls/355
Co-authored-by: miteruzo <miteruzo@naver.com>
Co-committed-by: miteruzo <miteruzo@naver.com>

backend/Gemfile

@@ -69,3 +69,5 @@ gem 'discard'
 gem "rspec-rails", "~> 8.0", :groups => [:development, :test]
 
 gem 'aws-sdk-s3', require: false
+
+gem 'rails-i18n', '~> 8.0.0'