I didn't want to express the application I'm working on in English as much as possible, so I investigated and summarized it.
Add the above Gem
Also at the terminal
rails g i18n_locale ja
To execute. With this command config/locales/ja.yml Is generated.
If you want to change the time display when displaying the time with the l method, It is good to put a correction on the 204th line. Also, if you want to prepare some patterns depending on the display location, you can customize it on lines 205 and 206.
I felt that it was a fairly important gem because I could customize and display my own units in Japanese.