Trying to install Discourse in an Ubuntu VM on Proxmox

Its basically the same guide as the Standard Install Guide, just without the Cloud steps (so starting from the Docker steps). I’m not looking to host this server in the Cloud (so not following them), I’m looking to host it in a VM on my server.

And the main Guide does not suggest what to do in case I run into a disk space issue like this. That’s why I’m asking here where would I have assign the extra disk space to get Discourse to start properly.