val username = usernameTextfield.text
val password = passwordTextfield.text
async(CommonPool) {
      val valid = if (username.contains("@"))
           AccountRestClient.login(LoginBean(email = username, password = password)).isValid()
      else
           AccountRestClient.login(LoginBean(username = username, password = password)).isValid()

      if (valid)
            postRunnable { changeScreen(LobbyScreen::class) }
}