The out of the box ASP.NET 5 Identity classes are straight forward and it is easy to setup and use, my problem however is that I'm working with a legacy system with existing user and permission tables that I have to customize the Identity system for. The Identity system seems very pluggable, but I can't find any proper documentation on how to write custom Identity classes. Is there any documentation on

1. How to write custom ASP.NET 5 Identity classes that can cater for legacy system user and permission tables
2. How do I setup the use of the custom Identity classes for use in a ASP.NET 5, MVC 6 application?