applying an object with a ICollection<Enum> type - asp.net-core

Question

In an ASP.NET 3.1 CORE project, using EF, I am trying to implement an object that holds a type of ICollection<Enum> type.
the problem is after reading some tutorials and trying to migrate it to my database something seems off, I will attach screenshots and code for more understanding.
this is the object class :
public class UsersCredentialsModel
{
[Key]
public string UserId { get; set; }
public ICollection<ServiceModel> Services { get; set; }
public string Username { get; set; }
public string Password { get; set; }
public string Hash { get; set; }
}
The ServiceModel class:
public class ServiceModel
{
[Key]
public string ServiceId { get; set; }
public Service Service { get; set; }
}
The Service Enum Class:
public enum Service : int
{
Badoo = 0,
Tinder = 1,
Grinder = 2,
OkCupid = 3
}
This is the AppDbContext class:
public class AppDbContext : IdentityDbContext<ApplicationUser>
{
public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
{
}
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<Message>().Property(m => m.Service).HasConversion<int>();
builder.Entity<ApplicationUser>().HasMany<Message>(m => m.Messages).WithOne(u =>
u.User).IsRequired();
builder.Entity<ServiceModel>().Property(m => m.Service).HasConversion<int>();
builder.Entity<UsersCredentialsModel>().HasMany(s => s.Services);
base.OnModelCreating(builder);
}
public DbSet<UsersCredentialsModel> UsersCredentialsModels { get; set; }
public DbSet<ServiceModel> ServiceModel { get; set; }
public DbSet<Message> Messages { get; set; }
public DbSet<CookieModel> CookieModel { get; set; }
public DbSet<ProjectionModel> ProjectionModel { get; set; }
}
This is a picture of the UsersCredentialsModel database schema:
** I believe that there should be a filed called "ServiceId" corresponding to the Id of the second table.
and finally a picture of the ServiceModel schema:
from what I understood you can't implement ICollection of type ENUM and you have to wrap it in a class so basically you need an object to hold the ENUM with an ID and another Id that holds the userId.
The problem is that UserCredentialsModel table should hold an Id property of ServiceId coming from ServiceModel table.
because the class has a field of ICollection but when migrating it does nothing