protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity <Auction>()
            .HasOne(auction => auction.AuctionDetail)
            .WithOne(auctionDetail => auctionDetail.Auction)
            .HasForeignKey <AuctionDetail>(auctionDetail => auctionDetail.AuctionId);

            // Seed data.
            DataSeeder seeder = new DataSeeder();

            List <Make> makes = seeder.GenerateCarMakes();

            modelBuilder.Entity <Make>().HasData(makes);

            List <Model> models = seeder.GenerateCarModels();

            modelBuilder.Entity <Model>().HasData(models);

            List <Trim> trims = seeder.GenerateCarTrims();

            modelBuilder.Entity <Trim>().HasData(trims);
        }