ASP.NET Identity remove column from AspNetUsers table

When I use ASP.NET Identity first code approach, I want to generate columns in AspNetUsers table in my own way. I don’t need to have stored multiple columns with null values. I just need columns Id, SecurityStamp and UserName.
Only post, that I’ve found is here: AspNet Identity 2.0 Email and UserName duplication , but it is still unsloved (due to error in Santosh comment).

Best practices for integrating ASP.NET Identity – do they exist?

I’m using ASP.NET Identity with a new website and there don’t seem to be many (any?) examples of how to do this in a decoupled manner. I do not want my domain model’s DomainUser class to have to inherit from Microsoft.AspNet.Identity.EntityFramework.User, so I’ve created a class that looks like this: