Added Laravel's env helper

config/autoload/url-shortener.global.php

@@ -1,12 +1,14 @@
 <?php
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+
 return [
 
     'url_shortener' => [
         'domain' => [
-            'schema' => getenv('SHORTENED_URL_SCHEMA') ?: 'http',
-            'hostname' => getenv('SHORTENED_URL_HOSTNAME'),
+            'schema' => env('SHORTENED_URL_SCHEMA', 'http'),
+            'hostname' => env('SHORTENED_URL_HOSTNAME'),
         ],
-        'shortcode_chars' => getenv('SHORTCODE_CHARS'),
+        'shortcode_chars' => env('SHORTCODE_CHARS', UrlShortener::DEFAULT_CHARS),
     ],
 
 ];