Add public link filter to Gallery admin

photologue/admin.py

@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 from django.contrib import admin
+from django.contrib.admin import EmptyFieldListFilter
 from django.utils.translation import gettext_lazy as _
 
 from .models import Gallery, Photo, Tag
@@ -10,7 +11,7 @@ from .models import Gallery, Photo, Tag
 
 class GalleryAdmin(admin.ModelAdmin):
     list_display = ("title", "date_start", "photo_count", "get_tags")
-    list_filter = ["date_start", "tags"]
+    list_filter = ["date_start", "tags", ("public_token", EmptyFieldListFilter)]
     date_hierarchy = "date_start"
     prepopulated_fields = {"slug": ("title",)}
     model = Gallery