public static function addFav($drink)
{
$user = $_SESSION['user'];
$errors = Drink::validateFavoriteDoesntExist($user, $drink);
if (count($errors) > 0) {
Redirect::to('/drink', array('message' => $errors[0]));
}
Drink::addFavorite($user, $drink);
Redirect::to('/drink', array('message' => 'Favorite has been added.'));
}