Generally speaking you could also do the group setup after the initial user is created. The idea behind bootstrap is meant to really just solve chicken-egg problem without encoding defaults into the db migrations.
With all of that said, it's fine to expand keystone-manage bootstrap to be more flexible. Just keep in mind it shouldn't be "the way" to populate everything in keystone - it should be the basic necessities so that the basic setup can be finished.
Generally speaking you could also do the group setup after the initial user is created. The idea behind bootstrap is meant to really just solve chicken-egg problem without encoding defaults into the db migrations.
With all of that said, it's fine to expand keystone-manage bootstrap to be more flexible. Just keep in mind it shouldn't be "the way" to populate everything in keystone - it should be the basic necessities so that the basic setup can be finished.