Part of https://github.com/docker/docker-ce-packaging/issues/1186
Adds the required systemd-sysusers configuration to the
moby/moby repo. This will be used by downstream package
maintainers (RPM, DEB etc) as a replacement to the
`groupadd` postinstall commands.
It's generally recommended to use sysusers since it is
more of a declarative method of defining these service
accounts and groups.
This configuration file specifies a group ("g") named
"docker" should be created with an automatic GID
allocation ("-").
Signed-off-by: Robert Sturla <robertsturla@outlook.com>
