gistfile1.cs

public class User : IPrincipal
    {
        public User(string username, IEnumerable<string> roles)
        {
            Username = username;
            Roles = roles;
        }

        public string Username { get; private set; }
        public IEnumerable<string> Roles { get; private set; } 

        public bool IsInRole(string role)
        {
            return Roles.Any(x => x.Equals(role, StringComparison.InvariantCultureIgnoreCase));
        }

        public IIdentity Identity
        {
            get { return new GenericIdentity(Username);}
        }
    }