Import a package including history

The code of an existing repository can be imported with the following command:

git subtree add --prefix=third_party/git master

You can easily pull back changes from the upstream repository into that folder

git subtree pull --squash --prefix=third_party/git gitgit/master

You can also push changes back upstream as follows:

git subtree push --prefix=third_party/git gitgit/master

This means we can update our sources during development with the following commands:

git subtree pull --squash --prefix=DistributionPackages/drk_template2016 git/master