Watch out: Craft Commerce: Numeric SKUs will not work with this plugin

If you use Craft Commerce and your products have a numeric value, this plugin will remove it from the search index and the product is not searchable anymore via the SKU.

ostark/craft-relax/src/SearchIndex/InsertFilter/UselessKeywords.php:21 
```php
 // Don't index numbers
if (is_numeric($keywords)) {
    return true;
}
```

So watch out! 

