# on the Dokku host
# install the letsencrypt plugin
# plugin installation requires root, hence the user change
sudo dokku plugin:install https://github.com/dokku/dokku-letsencrypt.git

# set global email for letsencrypt
dokku letsencrypt:set --global email your-email@your.domain.com

# set a custom domain that you own for your application
dokku domains:set ruby-getting-started ruby-getting-started.your.domain.com

# enable letsencrypt
dokku letsencrypt:enable ruby-getting-started

# enable auto-renewal
dokku letsencrypt:cron-job --add