Use docker to follow the contribution

[geekabel]

I think we need a docker environment to contribute to the project with PHP8.0 because in my case I don't think everyone uses PHP8.0 on their computer by default.

[GaryClarke]

Reasonable suggestion...I'd merge it in if someone wants to have a go at it.

[geekabel]

Nice ! I'v already set it up in my local environment !