public Trip CreateTrip(string origin, string destination, User user)
        {
            var newTrip = new Trip() {
                Id = Guid.NewGuid(),
                Origin = origin,
                Destination = destination,
                UserId = user.Id,
                Username = user.Name,
                CreatedAt = DateTime.Now
            };
            trips.Add(newTrip);

            return newTrip;
        }
        private System.Net.HttpStatusCode getPassenger(Guid id, ref User passenger)
        {
            // TODO extract this method

            // TODO move URI to a configuration file
            var userManagementClient = new RestClient("http://localhost:5000");

            var request = new RestRequest("api/users/{id}", Method.GET);
            request.AddUrlSegment("id", id.ToString());

            var response = userManagementClient.Execute<User>(request);

            // set the passenger
            passenger = response.Data;

            return response.StatusCode;
        }