Yes, since this is such an important feature, I decided to devote more energy to it in the 1.0 release. This is now included in Pijul: if you compile Pijul with --features git (i.e. cargo install pijul --version "~1.0-alpha" --features git), you’ll get a pijul git command, which imports a Git repository, and remembers a mapping between commits and patches so that you can even keep working in Git, and import your commits incrementally.
(There are probably some caveats to this last thing).
Note that we’ll change the repository format in a few days, before release the beta version, and this will break existing repositories. The new backend is at least five times faster, and also allows for less memory copies, so I’m expecting a big performance improvement.