Helper for Vagrant Docker provider

For no linux host machine which needs boot2docker VM, especially Mac.
Use NFS synced folder instead of rsync.

Note) But you may prefer Docker provisioner to Docker provider on Mac. https://github.com/YungSang/vagrant-docker-helper/tree/master/provisioner

Boot up boot2docker VM (= `vagrant up`)

$ make up

Remake a container (= `vagrant reload`)

$ make provision

SSH to boot2docker VM

$ make ssh

Reload boot2docker VM

$ make reload

Suspend boot2docker VM

$ make suspend

Stop boot2docker VM

$ make stop

Destroy boot2docker VM

$ make clean

Set DOCKER_HOST to use Docker from a local machine

$ export DOCKER_HOST="tcp://`make ssh-config | sed -n "s/[ ]*HostName[ ]*//gp"`:2375"