Mapping Auction DomainModel

//Mapping Auction DomainModel - Cornerstone T363
protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            //AUCTIONBID - Properties
            modelBuilder.Entity<AuctionBid>().Property(p => p.Offer).IsRequired();

            //CHATMESSAGE - Properties
            modelBuilder.Entity<ChatMessage>().Property(p => p.Time).IsRequired();
            modelBuilder.Entity<ChatMessage>().Property(p => p.Message).IsRequired();


            //AUCTIONITEM - Properties
            modelBuilder.Entity<AuctionItem>().Property(p => p.Headline).IsRequired().HasMaxLength(50);
            modelBuilder.Entity<AuctionItem>().Property(p => p.Description).IsRequired().HasMaxLength(100);
            modelBuilder.Entity<AuctionItem>().Property(p => p.OutputPrice).IsRequired();

            //USER - Properties
            modelBuilder.Entity<User>().Property(p => p.Name).IsRequired().HasMaxLength(50);
            modelBuilder.Entity<User>().Property(p => p.Lat).HasMaxLength(100);
            modelBuilder.Entity<User>().Property(p => p.Lng).HasMaxLength(100);

            //RELATIONS MAPPING
            modelBuilder.Entity<AuctionItem>()
                .HasRequired(m => m.User)
                .WithMany(t => t.AuctionItems)
                .HasForeignKey(m => m.UserId)
                .WillCascadeOnDelete(true);

            modelBuilder.Entity<ChatMessage>()
                .HasRequired(m => m.User)
                .WithMany(t => t.ChatMessages)
                .HasForeignKey(m => m.UserId)
                .WillCascadeOnDelete(true);

            modelBuilder.Entity<AuctionBid>()
                .HasRequired(m => m.AuctionItem)
                .WithMany(t => t.AuctionBids)
                .HasForeignKey(m => m.AuctionItemId)
                .WillCascadeOnDelete(true);

            modelBuilder.Entity<AuctionBid>()
                .HasRequired(m => m.User)
                .WithMany(t => t.AuctionBids)
                .HasForeignKey(m => m.UserId)
                .WillCascadeOnDelete(false);

        }