[documentation] README "how to install" instructions seem incomplete

[phlummox]

Describe the bug

The "How to install?" instructions in the README imply that invoking docker compose up and copying in a course under the tasks directory is enough to get a minimal working system. But I don't think that's correct – a user needs to pull at least one suitable "environment" image.

To Reproduce

Steps to reproduce the behavior:

1. Clone the repo, and read the README, which advises running

https://github.com/INGInious/INGInious/blob/ad7ab7214eff7094c39d6c445b24786f090221df/README.rst?plain=1#L37

3. Create or clone a course - e.g. clone https://github.com/INGInious/demo-tasks.git and then cp -a demo-tasks/tutorial tasks/.
4. Select any task (e.g. '1. Getting started' from the tutorial)
5. Click "Edit task" on the left sidebar, then the "Environment tab"
6. Try to select a "Grading environment"

Expected behavior

Following the README should result in an instance with at least one grading environment.

Actual behavior

No grading environments are available. So any attempt to submit an answer to any task will result in a 'Environment not available' error.

Desktop (please complete the following information):

N/A

Additional context

I assume the README should advise users to, at a minimum, run

docker pull ghcr.io/inginious/env-default

And maybe other environments (e.g. env-python3?) - not yet having got through it, I'm not sure what the tutorial requires.

[nrybowski]

Thanks for the report. I would rather extend the docker-compose.yml file to build locally the default grading environment so that the project deployment from sources is self-contained.