Hi guys, i'm starting with petapoco to save my categories, buy im having a problem with the autoincrement,

I followed this example: http://www.nibble.be/?p=440, but i dont create nodes with the categories, i show them in a table, loading them from the DB, and everyone have Id = 0

This is my model:

[TableName("categories")]
    [PrimaryKey("CategoryId", autoIncrement = true)]
    public class Category
    {
        public Category() { }
        [PrimaryKeyColumn(AutoIncrement = true)]
        public int CategoryId { get; set; }
        public string Name { get; set; }
        public string Father { get; set; }
        public override string ToString()
        {
            return "Category: "+ Name ;
        }
    

This is my RegisterEvents

public class RegisterEvents : ApplicationEventHandler
    {
        protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            var db = applicationContext.DatabaseContext.Database;
            if (!db.TableExist("categories"))
            {
                db.CreateTable(false);
            }
        }
    }

And the controller:

public class CategoryApiController : UmbracoApiController
    {
        public IEnumerable GetAll()
        {
            var query = new Sql().Select("*").From("categories");
          return DatabaseContext.Database.Fetch(query);
        }
        public Category GetById(int id)
        {
            var query = new Sql().Select("*").From("categories").Where(x => x.CategoryId == id);
            return DatabaseContext.Database.Fetch(query).FirstOrDefault();
        }
        public Category PostSave(Category cat)
        {
            if (cat.CategoryId > 0)
             DatabaseContext.Database.Update(cat);
         else
             DatabaseContext.Database.Save(cat);
         return cat;
        }
        public int DeleteById(int id)
        {
            return DatabaseContext.Database.Delete(id);
        }
    }

i don't see where is the error, but i can't edit or delete items, because them all have the same id