Use Database Variable within config files

I'm using dimsav/laravel-translatable for multiple language input. I want the language list to be dynamic, hence the list of languages can be fetched from database. Code:

<?php
use Illuminate\Support\Facades\DB;


$language = DB::table('site_settings')
    ->where('key', 'language')
    ->first();

$languages = explode(',',$language->value);
return [


    'locales' => isset($languages)? $languages: [
        'en',
        'ne',
    ],
];

However I'm getting error:

RuntimeException in Facade.php line 218:
A facade root has not been set.

via Chebli Mohamed