Mapeamento da classe Categoria no NHibernate 3.2

Category.cs

using NHibernate.Driver;
using NHibernate.Mapping.ByCode;
using NHibernate.Mapping.ByCode.Conformist;

namespace workshop_Entity
{
    public class Category
    {
        public virtual int IdCategoria { get; set; }
        public virtual string Nome { get; set; }
        public virtual string Descricao { get; set; }
    }

    public class CategoryMap : ClassMapping<Category>
    {
        public CategoryMap()
        {

            Id(x => x.IdCategoria, m => m.Generator(Generators.Identity));
            Property(x => x.Nome, m => m.Length(SqlClientDriver.MaxSizeForLengthLimitedString + 1));
            Property(x => x.Descricao, m => m.Length(SqlClientDriver.MaxSizeForLengthLimitedString + 1));
        }

    }
}