Go vendoring

#!/bin/sh
if [ "$1" == "" ]; then
  echo "Usage: $0 <PROJECT_ROOT> <GITHUB_REPO>"
  exit 1
fi
if [ "$2" == "" ]; then
  echo "Usage: $0 <PROJECT_ROOT> <GITHUB_REPO>"
  exit 1
fi

$branch=$3
if [ "$branch" == "" ]; then
   branch=master
fi

cd $1
git submodule add https://github.com/${2}.git vendor/github.com/$2
cd vendor/github.com/$2
git checkout master
cd -
git add $2
git commit -m "Added github.com/$2"