add sort and filter to shift registrations

shiftregister/app/admin.py

@@ -1,4 +1,5 @@
 from django.contrib import admin
+from django.contrib.admin import DateFieldListFilter
 
 from .models import Room, Shift, Helper, ShiftRegistration, Message, LoginToken
 
@@ -42,6 +43,7 @@ class HelperAdmin(admin.ModelAdmin):
 @admin.register(ShiftRegistration)
 class ShiftRegistrationAdmin(admin.ModelAdmin):
     list_display = ("start_at", "room", "helper_name", "state")
+    list_filter = (("shift__start_at", DateFieldListFilter), "shift__room", "state")
 
     def room(self, obj):
         return obj.shift.room.name
@@ -49,6 +51,8 @@ class ShiftRegistrationAdmin(admin.ModelAdmin):
     def start_at(self, obj):
         return obj.shift.start_at
 
+    start_at.admin_order_field = "shift__start_at"
+
     def helper_name(self, obj):
         return obj.helper.name