Setting up multiple rails apps using nginx and Puma

Question

I have a web server serving multiple Rails applications using a combination of nginx and Passenger. This is pretty straightforward, because the Passenger install sets-up pretty much everything you need to connect to nginx.

I found "Rails app with Puma" that seems to explain how to set up nginx and Puma together. How would this configuration need to be modified in order to serve a second Rails application on the same server?

Also, this guide doesn't say anything about restarting the application automatically if there is a system reboot or some other issue. Is there a way to do that? The nginx + Passenger combo seems to do it by default.