设置Illuminate查询生成器 - Uncaught RuntimeException：尚未设置Facade根

I am trying to set up Illuminate query builder, so I can run queries like "DB::table('table')->where(...)" .. however I can't get it to work.

I downloaded Laravel throught composer (require laravel/laravel). Next I have created a index.php, where I am including composer autoload file. After that, I am trying to call a simple query:

\Illuminate\Support\Facades\DB::table('users')->get();

However it throws exception "Uncaught RuntimeException: A facade root has not been set.". I was not expecting it to work right away, because I didn't specified the database connection. But based on the message of this exception I am not much clever.

I found a solution here on SO to put this before using query builder:

$Capsule = new Capsule;
$Capsule->addConnection(config::get('database'));
$Capsule->setAsGlobal();
$Capsule->bootEloquent();

However the config::get('database') statement throws the same exception too. Which means I probably have to configure the config somehow too.

I have tried to include Laravel's bootstrap and boot it, but it does not change anything.

$app = require_once '\composer\vendor\laravel\laravel\bootstrap\app.php';
$app->boot();

Then I tried to set Config's facade app by this statement: Config::setFacadeApplication($app) After that, when I try to call Config::get('database'), it throws other exception Uncaught ReflectionException: Class config does not exist

Now I am out of ideas how to get it working. What am I missing here?

Solved by extending an Application class and defining config and db instances in bootstrap function, like this:

use Illuminate\Config\Repository;
use Illuminate\Database\Connectors\ConnectionFactory;
use Illuminate\Database\DatabaseManager;
use Illuminate\Foundation\Application;

class LaravelApp extends Application
{

    function boot()
    {
        parent::boot();

        $this->instance('config', new Repository(['database' => $this->getDBCfg()]));
        $this->instance('db', new DatabaseManager($this, new ConnectionFactory($this)));
    }

    private function getDBCfg(){
        return [

            'default' => env('DB_CONNECTION', 'mysql'),

            'connections' => [

                'mysql' => [
                    'driver' => 'mysql',
                    'host' => env('DB_HOST', 'localhost'),
                    'port' => env('DB_PORT', '3306'),
                    'database' => env('DB_DATABASE', 'test'),
                    'username' => env('DB_USERNAME', 'root'),
                    'password' => env('DB_PASSWORD', ''),
                    'unix_socket' => env('DB_SOCKET', ''),
                    'charset' => 'utf8mb4',
                    'collation' => 'utf8mb4_unicode_ci',
                    'prefix' => '',
                    'strict' => true,
                    'engine' => null,
                ],

            ],

        ];
    }
}

Client code looks like this:

$laravelApp = new LaravelApp(__DIR__);
$laravelApp->boot();
Config::setFacadeApplication($laravelApp);
var_dump(\Illuminate\Support\Facades\DB::table('test')->get());

Thanks for help in comments