private User ChangeCurrentTown(string username, string townName)
        {
            if (!townService.Exist(townName))
            {
                throw new ArgumentException($"Value {townName} not valid.{Environment.NewLine}" +
                                            $"Town {townName} not found!");
            }

            User user = context.Users.First(u => u.Username == username);

            user.CurrentTown.Name = townName;

            context.SaveChanges();

            return(user);
        }