Update README.md

Updated the README for easier docker administration.  By putting in the --name flag in the docker run command this allows you to name your container which makes it easier to manage.  I also broke out the -p 80:80 command so people understand how the port mapping works.
Merge pull request #24 from vegasbrianc/patch-1

Update README.md
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/HouseOfAgile/docker-wordpress-multilang-nginx