Learn Rails by reading all the guides.
The missing manual for Production Rails app.
Also checkout Upcase by Thoughtbot.

Just Use Heroku

To grow your App into a Monolith. You can focus on building your ideas instead of all the other things. There is a entire talk about this and this thread:

Two hot takes that I believe apply to 90% of all software teams:

1. You'd be better off on a PaaS like Heroku or Next than whatever custom AWS/cloud you've built
2. Postgres can do whatever you'd want from a non-RDBMS application data store. And faster. With fewer compromises

— Justin Searls (@searls) March 20, 2019

Here is a real world case study.

Who to find more inspirations

• Jon Yongfook

But does it scale?

It definitely scales with efforts of course. Consult Speedshop Blog and Newsletter by Nate Berkopec for practical performance tips. Read engineering blogs from companies with scale.

Thanks the team

Thanks core contributors like Aaron Patterson, Rafael Mendonça França, David Heinemeier Hansson, Jeremy Daer, Ryuta Kamizono, and other 5500+ people.

Open Source Rails apps

If you‘re new and want to learn how to do things with Rails in real-life apps:

Active: bluedoc, rubyapi.org, dev.to, Lobste.rs, rubygems.org
Inactive but good to look at Pull Requests: Hound, Upcase