public async Task Login(string email, string senha)
{
Settings.UserToken = await firebaseAuthenticator.LoginWithEmailPassword(email, senha);
Settings.UserKey = await firebaseHelper.GetUserKey(email);
var pessoa = await firebaseHelper.GetPerson(email);
Settings.UserName = pessoa.NOME;
Settings.UserEmail = pessoa.EMAIL;
Settings.UserType = pessoa.TIPO;
MessagingCenter.Send(EventArgs.Empty, "GoToLogin");
}