simplify urls and customflatpages

fet2020/gallery/urls.py

@@ -1,10 +1,12 @@
 from django.urls import path
 
+from . import apps
 from . import views
 
+app_name = apps.GalleryConfig.name
 
 urlpatterns = [
-    path("", views.index, name="gallery"),
+    path("", views.index, name="index"),
     path("<slug:slug>/", views.show_album, name="album"),
     path("draft/<slug:slug>/", views.show_draft_album, name="draft-album"),
 ]