Script: delete git branch and switch back to master

I call this script git-done

current_branch=$(git rev-parse --abbrev-ref HEAD)

if [ $current_branch == "master" ]
then
  echo "You're already on master"
  exit 0
else
  echo "switching to master"
  git checkout master
  echo "deleting $current_branch..."
  git-delete-branch $current_branch
fi