Generic Repository using Entity Framework

EntityFramework.cs

using Library.Models;
using Library.EF;

namespace Abstractions
{
  public interface IKeyedModel
  {
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
  }

  public class GenericContext<T> : DbContext where T : class, IKeyedModel
  {
    public DbSet<T> Items { get; set; } = default!;
  }

  public interface IRepository<T> where T : class, IKeyedModel
  {
    public GenericContext<T> Context() => new GenericContext<T>();

    public T Select(int id) => Context().Items.Single(x => x.Id == id);

    public IQueryable<T> Select() => Context().Items;

    public void Insert(T item)
    {
      var context = Context();
      context.Items.Add(item);
      context.SaveChanges();
    }

    public void Update(T item)
    {
      var context = Context();
      context.Items.Attach(item);
      context.SaveChanges();
    }

    public void Delete(int id)
    {
      var context = Context();
      var item = context.Items.Single(x => x.Id == id);
      context.Items.Remove(item);
      context.SaveChanges();
    }
  }
}

namespace Models
{
  [Table(name: "User")]
  public class User : IKeyedModel
  {
    public int Id { get; set; }
    public string Name { get; set; } = default!;
  }
}

namespace App
{
  public class UserRepository : IRepository<User> {  /* empty */ }
}