add purchase and sold price

Models/Vehicle.cs

@@ -10,6 +10,8 @@
         public string LicensePlate { get; set; }
         public string PurchaseDate { get; set; }
         public string SoldDate { get; set; }
+        public decimal PurchasePrice { get; set; }
+        public decimal SoldPrice { get; set; }
         public bool IsElectric { get; set; } = false;
         public bool UseHours { get; set; } = false;
         public List<ExtraField> ExtraFields { get; set; } = new List<ExtraField>();