Add custom field in Prestashop 1.7.6 category with a module. How to save in database?

$cat = new Category((int)$params['id']);
$cat->color= $data['color'];
$cat->update();

Try to update like this:

$query = "UPDATE `"._DB_PREFIX_."category_lang` SET color='".$data['color']."' WHERE id_category = '".(int)$params['id']."' ";
Db::getInstance()->Execute($query);