// ./backend-app/config/app.php

return [
    // ...
    'bootstrap' => [
        // some components ...
        'translation'
    ],
    'modules' => [
        // some modules ...
        'translation' => 'cookyii\modules\Translation\backend\Module',
    ],
    // ...
];

// ./common/commands/RbacCommand.php

class RbacCommand extends \rmrevin\yii\rbac\Command
{
    
    public $backendMerge = [
        // ...
        'cookyii\modules\Translation\backend\Permissions',
    ];
}