public void update() {
    camera.update();
    gameHud.update(camera);

    if (Gdx.input.isKeyJustPressed(Keys.I)) {
      System.out.println("Saving");
      WorldIO.saveWorld(world);
    }

    world.update(camera);
  }
 @Override
 public void pause() {
   WorldIO.saveWorld(world);
   Timer.stopGameTime();
 }
 @Override
 public void onBackPressed() {
   WorldIO.saveWorld(world);
   Timer.stopGameTime();
 }