How Discourse deals with upgrades

I am a happy discourse user.
I would like to know how Discourse deals with upgrades so that I can implement something similar.
I know it is Docker-based!
Is it watchtower?

Discourse has a web UI for updates located at /admin/upgrade

Additionally, ./launcher can be used to rebuild discourse with latest code using
./launcher rebuild app

Are asking about how you might be able to create base images and deploy updates? Or do you want to duplicate what Launcher does for a different application?

Either way, then there are many topics about the different approaches. Just search for ā€œdocker composeā€ in this forum. But the best topic for you on updating with Discourse Launcher may be this one:

@itsbhanusharma, yes i was trying to duplicate the launcher or updater. I just realized that it is not that hard especially using Golang.