Add Dockerfile for gh-pages site

[garethrees]

Add Dockerfile

Avoid having to faff with local dependencies.

docker compose build
docker compose up
open http://0.0.0.0:4000

[skip changelog]

[gbp]

Think we need a .dockerignore file as when building the image the whole current directory is copied into the image, which in my case is gigabytes in size!

Something like:

.*
cache/
commonlib/
config/
coverage/
db/
files/
gems/
lib/
public/
storage/
tmp/

[gbp]

No point in this as its already in the Gemfile.lock and could install a different versions than we're really using.

Suggested change

RUN gem install bundler jekyll

[gbp]

Lets keep the image and small as possible

Suggested change

	FROM ruby:3.2
	FROM ruby:3.2-slim
	RUN apt-get update -qq && \
	apt-get install -y \
	build-essential \
	git \
	&& rm -rf /var/lib/apt/lists/*

[gbp]

This would be good, if it works?

Suggested change

	CMD ["bundle", "exec", "jekyll", "serve", "--host", "0.0.0.0"]
	CMD ["bundle", "exec", "jekyll", "serve", "--host", "0.0.0.0", "--livereload"]

[gbp]

Docker warns against including a version now. We should remove.

Suggested change

version: '3.8'

[garethrees]

Closing for now; will reopen next time someone needs this