@klawitterb ah brilliant. I didn't know rails does not serve public files in production mode. I managed to get it to work as well.
Indeed, it has no multi-user yet but seems OK for a single user. Apparently, you can create more users like https://github.com/chrisvel/wreeto_official#52-create-a-new-account-rails-console (but looks like the users have no connection to one another. no sharing etc)