Opening (importing) git repo from command line

[rtlxndr]

I want it to import new repo or open already added repo using command line argument, when launching application.
Feature requires to decide if multi-instance workflow should be supported (multiple main windows with different repos opened/focused). And how they should use eclipse workspace.
Easiest would probably be force single instance (if workspace in use) + activating window + adding repo if not added + select this repo.