There’s literally no way to owe anyone a beer ever, to solve this I’ve written a small piece of software so you can get a digital IOU that you owe (or are owed) a beer. (/s)
But seriously, this is an example application for how DAML works and all the nice features it gives you for free. The entire backend of this application is 32 lines of code and it enforces 2 contracts between two parties which can collectively exercise 4 different actions.
Code: https://github.com/anthonylusardi-da/o_beer
Live site: https://beer.woah.xyz