function addBook(Book $newBook)
{
    $db = new ServerDatabase();
    $db->newQuery("INSERT INTO book (author, title, image, category) VALUES ('%1', '%2', '%3', %4)");
    $db->addParameter($newBook->author);
    $db->addParameter($newBook->title);
    $db->addParameter($newBook->image);
    $db->addParameter($newBook->category);
    $db->execute();
    return $db->getLastInsertId() > 0;
}