Made sessions cleaner more specific.

misago/sessions/management/commands/clearsessions.py

@@ -1,4 +1,5 @@
 from datetime import timedelta
+from django.conf import settings
 from django.core.management.base import BaseCommand
 from django.utils import timezone
 from misago.sessions.models import Session
@@ -9,5 +10,5 @@ class Command(BaseCommand):
     """
     help = 'Clears users sessions'
     def handle(self, *args, **options):
-        Session.objects.filter(last__lte=timezone.now() - timedelta(hours=12)).delete()
+        Session.objects.filter(last__lte=timezone.now() - timedelta(seconds=settings.SESSION_LIFETIME)).delete()
         self.stdout.write('Sessions have been cleared.\n')