Auction DomainModel

//DomainModel Auction - Cornerstone T363
[Serializable]
    [DataContract]
    [DisplayColumn("Name")]
    public partial class User : PersistentEntity
    {
        [DataMember]
        public string Name { get; set; }

        [DataMember]
        public string Lat { get; set; }

        [DataMember]
        public string Lng { get; set; }

        [DataMember]
        public virtual IList<ChatMessage> ChatMessages { get; set; }

        [DataMember]
        public virtual IList<AuctionItem> AuctionItems { get; set; }

        [DataMember]
        public virtual IList<AuctionBid> AuctionBids { get; set; }
    }

    [Serializable]
    [DataContract]
    [DisplayColumn("Headline")]
    public partial class AuctionItem : PersistentEntity
    {
        [DataMember]
        public string Headline { get; set; }

        [DataMember]
        public string Description { get; set; }

        [DataMember]
        public int OutputPrice { get; set; }

        [DataMember]
        public bool Active { get; set; }

        [DataMember]
        public virtual IList<AuctionBid> AuctionBids { get; set; }

        [DataMember]
        public int UserId { get; set; }
        [DataMember]
        public virtual User User { get; set; }
    }

    [Serializable]
    [DataContract]
    [DisplayColumn("Offer")]
    public partial class AuctionBid : PersistentEntity
    {
        [DataMember]
        public int Offer { get; set; }

        [DataMember]
        public int UserId { get; set; }
        [DataMember]
        public virtual User User { get; set; }

        [DataMember]
        public int AuctionItemId { get; set; }
        [DataMember]
        public virtual AuctionItem AuctionItem { get; set; }
    }

    [Serializable]
    [DataContract]
    [DisplayColumn("Message")]
    public partial class ChatMessage : PersistentEntity
    {
        [DataMember]
        [Required]
        public string Message { get; set; }

        [DataMember]
        [Required]
        public string Time { get; set; }

        [DataMember]
        public int UserId { get; set; }
        [DataMember]
        public virtual User User { get; set; }
    }