如何在Laravel中跨两个数据库保存实体(背包)

'database2' => [
    'driver' => 'mysql',
    'host' => 'localhost',
    'database' => 'database2',
    'username' => 'root',
    'password' => 'password',
    'charset' => 'utf8mb4',
    'collation' => 'utf8mb4_unicode_ci',
    'prefix' => '',
    'strict' => true,
    'engine' => null,
],

protected $connection = 'database2';

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateBackpacksTable extends Migration
{
    public function up()
    {
        Schema::create('backpacks', function (Blueprint $table) {
            $table->id();
            $table->string('name');
            $table->text('description');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('backpacks');
    }
}

$backpack = new Backpack;
$backpack->name = 'My Backpack';
$backpack->description = 'This is my backpack.';
$backpack->save();