Sets the default locale.
I18n.default_locale = "ja"
Sets the locale.
I18n.locale = "ja-JP"
Sets the supported locales.
I18n.set_supported_locales("ja-JP", "ko-KR", ...)
Gets the supported locales.
Sets the supported locales as an Array.
I18n.supported_locales = ["ja-JP", "ko-KR", ...]
[Validate]