Cache tag URL

boards/models/tag.py

@@ -125,6 +125,7 b' class Tag(models.Model, Viewable):'
     def get_archived_thread_count(self) -> int:
         return self.get_thread_count(status=STATUS_ARCHIVE)
 
+    @cached_result()
     def get_absolute_url(self):
         return reverse('tag', kwargs={'tag_name': self.get_name()})