Create boot2docker-together-with-virtualbox-guest-additions.md

original post: [boot2docker together with VirtualBox Guest Additions - How to mount /Users into boot2docker](https://medium.com/boot2docker-lightweight-linux-for-docker/boot2docker-together-with-virtualbox-guest-additions-da1e3ab2465c).

Signed-off-by: Peter Zhang nouoo#msn.com
Merge pull request #54 from duobei/master

Create boot2docker-together-with-virtualbox-guest-additions.md