1. Add the `i18n-tasks-use` comments where the unrecognized translations are used (such as the date and activerecord ones).
   This way your unused list will correspond to the keys that are not actually used, and you can keep your files clean by using the `remove-unused` task.
2. Using `activerecord` translations is coupling your ActiveRecord layer to your UI, which is the wrong level of abstraction. They will cause issues when refactoring.
   I recommend avoiding these entirely.
3.  I'd also suggest mentioning reference keys. These are invaluable in engines and larger apps. E.g.:
   

   en:
     greetings: Hello guest!
     visitors:
       index:
         greetings: :greetings

4. You can use `translate-missing` instead of `add-missing` to add Google-Translated values Japanese version.
5. Another useful task is `i18n-tasks mv` for renaming keys.

If you're looking to not run the deployment as root / a passwordless sudoer, have a look at these playbooks: https://github.com/thredded/thredded-ansible

I built them to deploy a Rails app with Thredded but it should work for any Rails app.