Create a Docker image to support Attempt This Online

[mbomb007]

I'd like to see this language on ATO.

https://github.com/attempt-this-online/attempt-this-online/blob/main/docs/contributing.md

[m-ender]

I don't currently have the time to look into this, but I'd be happy to accept a pull request.

[mbomb007]

attempt-this-online/attempt-this-online#24 (comment)