Simpler docker usage

[tpluscode]

I would like to propose much simplified instructions for running from docker locally. Basically all one needs is a docker-compose and a dockerfile to build a local image with an installation of bike shed. No building from sources and manual volume setup

.Dockerfile

FROM python:buster

RUN pip install bikeshed
RUN bikeshed update

ENTRYPOINT ["bikeshed"]
CMD ["--help"]

docker-compose.yml

version: "3"
services:
  bikeshed:
    build:
      context: .
      dockerfile: bs.Dockerfile
    volumes:
    - .:/data

Usage

The usage is as simple as it gets, for example:

docker-compose run --rm bikeshed watch /data/spec/index.bs

[tabatkins]

This certainly looks a lot better! Since I have no familiarity with Docker at all, would you be willing to PR the docs with these code samples, replacing the current instructions?

[tpluscode]

@tabatkins