sessionauth/login.go
func AuthenticateSession(s sessions.Session, user User) error {
	user.Login()
	return UpdateUser(s, user)
}
func AuthenticateSession(s sessions.Session, user User) error {
	user.Login()
	return UpdateUser(s, user)
}
// AuthenticateSession will mark the session and user object as authenticated. Then
// the Login() user function will be called. This function should be called after
// you have validated a user.