Entity framework Core with Identity and ASP.NET Core 1.1 Seeding

Archer, to seed data to a database in ASP.NET core you should first create a class, you could call this DbInitializer, and it should look something like this.

public static class DbInitializer
{
    public async static void InitializeAync(ApplicationDbContext context, UserManager<ApplicationUser> userManager, RoleManager<IdentityRole> roleManager)
    {
        context.Database.EnsureCreated();

        // check if any users exist.
        if (context.Users.Any())
        {
            return;   // exit method, Database has been seeded
        }

        string[] roleNames = {"Admin", "Member" };
        IdentityResult roleResult;
        // loop through roleNames Array
        foreach (var roleName in roleNames)
        {
            var roleExist = await RoleManager.RoleExistsAsync(roleName);
            //check if role exists
            if (!roleExist)
            {
                // create new role
                roleResult = await RoleManager.CreateAsync(new IdentityRole(roleName));
            }
        }

        //create an array of users 
        var users = new ApplicationUser[];
       {
            new ApplicationUser
            {
                FirstName = "John",
                LastName = "doe",
                UserName = "johndoe",
                Email = "johndoe@email.com",
            };

           new ApplicationUser
           {
               FirstName = "James",
               LastName = "doe",
               UserName = "jamesdoe",
               Email = "jamesdoe@email.com",
           };
        }

        //loop through users array
        foreach (ApplicationUser _user in users)
        {
            // create user
            await userManager.CreateAsync(_user, "pa$$w0rd");
            //add user to "Member" role
            await UserManager.AddToRoleAsync(_user, "Member");
        }

    }
}

Next, you should call your InitializeAsync helper method in the DbInitializer class from the Configure method in the Startup class. like so

public async void Configure( ApplicationDbContext context, UserManager<ApplicationUser> userManager, RoleManager<IdentityRole> roleManager)
{
      DbInitializer.InitializeAync(context, userManager);
}

and that should do the trick