How to Add a Primary Key to the Products Model

I am new to MVC, and I'm studying the MVC Core 2 book by Freeman (see below).

As I go through the code to build a modest product inventory display, I'm at the point where

I need to create my first database migration. So at the command prompt, I typed:

> dotnet ef migrations add Initial

The error message says my products class requires a primary key! How do I provide it? Freeman

does not cover that in the book (that I can find).

Thanks for any help on this!

Corey

cf. Pro ASP.NET Core MVC 2, by Adam Freeman, APress, 7th Edition, 2017