devcontainer: support docker-compose

[johnstcn]

Devcontainer spec supports specifying a compose file

e.g.

	"dockerComposeFile": "docker-compose.yml",

Example: https://github.com/BrunoQuaresma/openticket/blob/main/.devcontainer/devcontainer.json

[jasclarke24]

This would be an awesome feature. We run a lot of dev environments with multiple containers for testing and rapid integration. What is the recommended way of doing this now, multiple containers in the template?

[johnstcn]

What is the recommended way of doing this now, multiple containers in the template?

Yeah that's honestly the best way right now. We're working on an alternative method of using devcontainers that should more seamlessly enable using @devcontainers/cli or similar existing Devcontainer tooling.

[tomtom5152]

I notice #107 and #135 both mention the same feature set, with the latter claiming it is a massive overhaul to add support for it. Is there still the plan to switch to the @devcontainers/cli tooling or something else? Happy to help out with this if I can, but some overall guidance on where the project wants to take it would be very helpful thanks

[harrismcc]

I'll just +1 this, this is the killer feature for my team that would allow us to use Coder since we use docker-compose with devcontainers to spin up our database and other supporting services!