Sharing a folder within a dev container

[zagreusinoz]

I've got a dev container working which works great, it serves a web app on port 80 from the folder /html

My code is in the workspaces/test folder. I'd like to share a folder between /html and /workspaces/test/html so that I can work on the code and can commit it to my repo.

If I was using docker-compose I'd use the volumes section and it would work great, however I can't work out how to do the same thing within my dev container. I tried using "mounts" in .devcontainer.json however that either didn't do anything or crashed the build.

Feels like this should be easy but I'm feeling pretty dumb rn. :)

Thanks