fix issue#2 optional config error

django_daisy/admin.py

@@ -4,6 +4,7 @@
 from django.db import models
 from django.shortcuts import render
 from django.urls import reverse
+from django.utils.timezone import override
 
 from django_daisy.module_settings import DAISY_SETTINGS
 
@@ -76,14 +77,15 @@ def _build_app_dict(self, request, label=None):
             return app_dict
 
         modified_app_dict = app_dict.copy()
+        override_apps_config = getattr(settings, 'APPS_REORDER', {})
 
         for app_label, app_info in app_dict.items():
             # Add icon and divider title to each app
             app_info['icon'] = getattr(apps.get_app_config(app_label), 'icon', '')
             app_info['divider_title'] = getattr(apps.get_app_config(app_label), 'divider_title', '')
 
             # Apply additional settings to individual apps from APPS_REORDER in settings.py
-            if app_label in settings.APPS_REORDER:
+            if app_label in override_apps_config:
                 app_info.update(settings.APPS_REORDER[app_label])
 
         return modified_app_dict