this simplifies the compose file a bit, makes the dockerfile more
efficient and reintroduces the setup script that works with the new
image.
also adds a default 'bind' of 0.0.0.0 to the server block in
config.ini.example.
this changes the Dockerfile a bit to work with the current version
0.10.0 of writefreely, and removes the docker-setup script for now.
Kind of a work in progress but wanted to share with those interested.