Customizing Identity 3

Hi,

Can someone help me with ASP.NET Identity 3 on how to change the User PrimaryKey from String to Integer. And how to customise the Identity TableNames and FieldNames in the new Identity 3.

I do see a few on Identity 2.0 but not much information available online on customising ASP.NET Identity 3 (or I was not able to google well).

Regards,