I would suggest following the methodology used in the ASP.NET Identity Sample:
https://github.com/rustd/AspnetIdentitySample/tree/master/AspnetIdentitySample/Controllers
They use two Controllers: RolesAdminController
and UserAdminController
.
Using this scheme would allow for a seeded administrative account to then manage the roles and users of that site.
I suspect you could probably just copy those straight into a new project using the new Identity scheme with very few modifications to work properly. However, I haven't personally attempted doing that part myself.