pet project to notify me with my e-pass remaining credit
next:
- subscription endpoint
- scheduling ✔
- deploy on heroku ✔
- additional buildpack: https://github.com/jontewks/puppeteer-heroku-buildpack
- logging
- scalability / performance (2 workers pub/sub)
- unsubscribe if many errors received
- front-end
- subscription form
- stats