add lazy loading for entities

ReallifeGamemode.Server/Entities/VehicleMod.cs

@@ -14,7 +14,7 @@ namespace ReallifeGamemode.Server.Entities
 
         [ForeignKey("Vehicle")]
         public int ServerVehicleId { get; set; }
-        public ServerVehicle Vehicle { get; set; }
+        public virtual ServerVehicle Vehicle { get; set; }
 
         public int Slot { get; set; }
         public int ModId { get; set; }