NancyFX returning struct as Json

gistfile1.txt

public class HomeModule : NancyModule
	{
		public HomeModule ()
		{
			Get ["/"] = p => "hello";

			Get ["/{id}/{user}"] = p => {
				User user = new User(p.id,p.user);
				return Negotiate.WithModel(user);
			};
		}
	}

	public struct User
	{
		public string Id;
		public string Name;
		public User (string id, string name)
		{
			this.Id = id;
			this.Name = name;
			
		}
	}