use brew (cask) to install/update virtualbox, vagrant & boot2docker

setup.sh

echo "Making sure homebrew is installed"
command -v brew >/dev/null 2>&1 || ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

echo "Installing / updating homebrew packages & casks"
brew update
for pkg in docker boot2docker fig brew-cask; do
	if ! brew list -1 | grep -q "^${pkg}\$"; then brew install ${pkg}; else brew upgrade ${pkg} || true; fi
done
for cask in virtualbox vagrant; do
	brew cask install ${cask} --force
done

echo "Installing / updating vagrant plugins"
for plugin in vagrant-vbguest; do
	if ! vagrant plugin list | grep -q "^${plugin}\$"; then vagrant plugin install ${plugin};  fi
done
vagrant plugin update

echo "Installing / updating boot2docker"
boot2docker init || true
boot2docker stop || true
boot2docker upgrade
boot2docker start