improve Docker instructions

[SethTisue]

right now the README just says "run docker-compose up", but I found that on my MacOS 10.14 laptop, I needed to do the following:

• brew cask install VirtualBox docker
• brew install docker-machine docker-compose
• docker-machine start
• eval $(docker-machine env)
• docker compose up

and then later, if I want to shut it down,

• docker-machine stop

this is probably routine stuff for those familiar with Docker, but some of us are about as ignorant of Docker as we are of Ruby and Bundler :-)

the above commands seemed to work, and what I saw in my terminal window ended with:

jekyll_1  | Configuration file: /site/_config.yml
jekyll_1  |             Source: /site
jekyll_1  |        Destination: /site/_site
jekyll_1  |  Incremental build: disabled. Enable with --incremental
jekyll_1  |       Generating... 
jekyll_1  |                     done in 29.876 seconds.
jekyll_1  |  Auto-regeneration: enabled for '/site'
jekyll_1  |     Server address: http://0.0.0.0:4000

the readme says the site will be served at http://localhost:8080, but it isn't. I'm not sure why, perhaps it's because I'm on MacOS and not on Linux (except via VirtualBox)? how do I view the site? (visiting http://0.0.0.0:4000 doesn't work either)

/cc @kotobotov

[kotobotov]

http://0.0.0.0:4000 - that's inside container
which bind to out world with 8080 port,
VirtualBox may have own restriction, (also i think, in your case the result is available only inside VirtualBox).
about instructions: maybe better just link to https://docs.docker.com/install/ , and note about if you want to use site with docker you need install docker first

[SethTisue]

hmm, perhaps I should be using Docker Desktop for Mac https://docs.docker.com/docker-for-mac/docker-toolbox/ in order to leave VirtualBox out of it