I'm coming from MVC 5, and I love how easy it is to scaffold a new Core 2.1 app with authentication, especially with the CLI so I can stay in VS Code. That being said . . . I'm struggling a bit. I want to use .NET Core for the backend of a React app, and I need to add a few properties to the IdentityUser class(if this is still the right thing?) for some app-specific functionality. Anyways, from the start everything is contained in the Razor Class Library, which is cool, but also daunting to me. I need to modify registration and sign in controllers, either go with JWT or session based logins, and have a couple roles. I've read you can override the controllers - but I don't know exactly what they are. Does anyone know a good resource for learning about the new Identity setup geared towards SPAs? Not to mention, I'm used to implementing my own repositories and stuff, is that all taken care of for me or should I just override everything? Any help is appreciated.