How to initialize Git repos

[Felix Lechner]

Hi,

When I edit the config file manually, i.e. without public-inbox-init, I
see errors until messages are added, such as:

    ($INBOX_DIR/description missing)

or
    fatal: not a git repository (or any parent up to mount point /srv)
    Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
    error in git rev-parse --git-dir (cwd:.):

How may I initialize a new Git repo before adding any messages, please?

Kind regards
Felix