Cache user-specific ratings

bookwyrm/models/status.py

@@ -3,6 +3,7 @@ from dataclasses import MISSING
 import re
 
 from django.apps import apps
+from django.core.cache import cache
 from django.core.exceptions import PermissionDenied
 from django.core.validators import MaxValueValidator, MinValueValidator
 from django.db import models
@@ -373,6 +374,11 @@ class Review(BookStatus):
     activity_serializer = activitypub.Review
     pure_type = "Article"
 
+    def save(self, *args, **kwargs):
+        """clear rating caches"""
+        cache.delete(f"book-rating-{self.book.parent_work.id}-*")
+        super().save(*args, **kwargs)
+
 
 class ReviewRating(Review):
     """a subtype of review that only contains a rating"""