Laravel 5.3 Passport Custom Grants?

I know I am not the only person who has come up to this point. Does anyone know how to properly implement a custom grant in Laravel(5.3) Passport?

Or

Have a good link/tutorial to reference how to properly do it?

I know there's this package:

http://ift.tt/2eqHJYf

But I'm asking for a more "Do it yourself" approach.

Thank you in advance.

via Chebli Mohamed