async Task CreateRoles(IServiceProvider serviceProvider) {
    //initializing custom roles 
    var roleManager = serviceProvider.GetRequiredService<RoleManager<IdentityRole>>();
    var userManager = serviceProvider.GetRequiredService<UserManager<ApplicationUser>>();
    string[] roleNames = [Roles.Admin, Roles.User];

    foreach (var roleName in roleNames) {
        var roleExist = await roleManager.RoleExistsAsync(roleName);
        // ensure that the role does not exist
        if (!roleExist) {
            //create the roles and seed them to the database: 
            await roleManager.CreateAsync(new IdentityRole(roleName));
        }
    }

    // Here you create the super admin who will maintain the web app. This password will obviously be changed. 
    await AddAdminUser(userManager, "[email protected]", "password");
}

// This is used on an initial launch of the application.
async Task AddAdminUser(UserManager<ApplicationUser> userManager, string username, string password) {
    var user = await userManager.FindByEmailAsync(username);

    // check if the user exists
    if (user == null) {
        //Here you could create the super admin who will maintain the web app
        var seedUser = new ApplicationUser {
            UserName = username,
            Email = username,
            EmailConfirmed = true,
            FirstName = "George",
            LastName = "Bjork"
        };
        var createPowerUser = await userManager.CreateAsync(seedUser, password);
        if (createPowerUser.Succeeded) {
            //here we tie the new user to the role
            await userManager.AddToRoleAsync(seedUser, Roles.Admin);
        }
    }
}

dotnet ef database update