/**
* Save the user preferences.
*
* @param [String] $index user preference key array
* @param [Array] $tags products tags
*/
public static function setPreferences($index = '', $tags = [])
{
$user = \Auth::user();
if ($user) {
$userHelper = new UserHelper();
$categories = ProductsController::getTagsCategories($tags);
$user->preferences = $userHelper->preferencesToJson($user->preferences, $index, $tags, $categories);
$user->save();
}
}