//config.neon
    services:
        Users: Users(@database)

//Users.php
<?php

use Nette\Application\UI;
use Nette\Security as NS;

class Users
{
    private $db;

    public function __construct(Nette\Database\Connection $db)
    {
        $this->db = $db;
    }

    public function activeCompany($id)
    {
        return $this->db->table('users')->where('id=?',$id)->fetch()->company_id;
    }

}