Debug from a diff

It would be amazing if we could debug code within the diff or the file at that commit.

I see it working like this.

Select a few lines and click a run button. You would be running the code out of context but you could provide input to it to see what happens. This way you could debug code without checking out the branch on a minimal but very helpful level.

Every time the code runs it could run in a docker container that is newly created on each run. That way there is no chance of a security issue. As long as no one can escape the container. I know it's technically possible to escape a container but I'm sure that we can solve that problem.

Cc @ayufan @JobV @dzaporozhets