lumen - Fatal error: Class 'Memcached'

[matiux]

In a Lumen application, I need to work with more databases. So, according to documentation, I have created the "config" directory in my root and I have copied the database.php from /vendor/laravel/lumen-framework/config/database.php so I can define an array with all my databases (like in laravel).

The problem is that when I run my application, I get this error:

PHP Fatal error: Class 'Memcached' not found in ..../vendor/illuminate/cache/MemcachedConnector.php on line 52

I don't understand what say to my app to use Memcached... in "config" directory I have also copied cache.php, setting the default param as well:

'default' => env('CACHE_DRIVER', 'array')

although for now I don't need to use cache...

If I disable holidaypirates/bugsnag-lumen the response is right, 404 with "Sorry, the page you are looking for could not be found." message

How can I solve? Thanks