still trying to clarify how to add USB tethering to core-image-minimal

i may be going at this wrong, but i want to start with a minimal
image (as in, OE's core-image-minimal), and modify an OE local.conf
file to add what it takes to have full USB tethering functionality
(both USB storage and networking).

  i'm currently using the meta-beagleboard[-extras] layers to add the
gadget-init recipe to the mix, but it appears there's more work to do.
i'm not married to a core-image-minimal -- would it be easier to start
with one of the systemd-based, command-line angstrom images?

  i'm sure this can't be hard, i just haven't puzzled it out yet.