Solution 1:

I don't seed from the migration, instead use the context db initializer. My context derives from IdentityDbContext so I use this method to seed users and roles:

Call an initializer from ctor:

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    private readonly IHttpContextBaseWrapper _httpContextBaseWrapper;

    static ApplicationDbContext()
    {
        // Set the database intializer which is run once during application start
        // This seeds the database with admin user credentials and admin role
        Database.SetInitializer(new ApplicationDbInitializer());
    }
...

Then my seed code:

public class ApplicationDbInitializer : CreateDatabaseIfNotExists<ApplicationDbContext>
{
    protected override void Seed(ApplicationDbContext context)
    {
        InitializeIdentityForEF(context);
        base.Seed(context);
    }

    public static void InitializeIdentityForEF(ApplicationDbContext db)
    {

        if (!db.Users.Any())
        {
            var roleStore = new RoleStore<IdentityRole>(db);
            var roleManager = new RoleManager<IdentityRole>(roleStore);
            var userStore = new UserStore<ApplicationUser>(db);
            var userManager = new UserManager<ApplicationUser>(userStore);

            // Add missing roles
            var role = roleManager.FindByName("Admin");
            if (role == null)
            {
                role = new IdentityRole("Admin");
                roleManager.Create(role);
            }

            // Create test users
            var user = userManager.FindByName("admin");
            if (user == null)
            {
                var newUser = new ApplicationUser()
                {
                    UserName = "admin",
                    FirstName = "Admin",
                    LastName = "User",
                    Email = "[email protected]",
                    PhoneNumber = "5551234567",
                    MustChangePassword = false
                };
                userManager.Create(newUser, "Password1");
                userManager.SetLockoutEnabled(newUser.Id, false);
                userManager.AddToRole(newUser.Id, "Admin");
            }
...