Setting up git identities

gistfile1.txt

https://news.ycombinator.com/item?id=22672491

You can also do a per-directory _global_ git configuration, e.g.
in .gitconfig, you say:

    [user]
        name = Me Myself
        email = personal@example.com
        signingkey = D34DB44F

    [includeIf "gitdir:~/src/github.com/work_org/"]
        path = ~/.gitconfig_work
Then in ~/.gitconfig_work:
    [user]
        name = Me Myself
        email = work@example.com
        signingkey = D34DC0D4
    
    [core]
        sshCommand = ssh -i ~/.ssh/work_ed25519