add KarmaKey.history()

calculates the value of the score at every point in the score's history.
might be slow, unsure yet

dr_botzo/karma/models.py

@@ -52,6 +52,21 @@ class KarmaKey(models.Model):
                 return rank+1
         return None
 
+    def history(self):
+        """Determine the score for this karma entry at every delta."""
+
+        history = []
+
+        entries = KarmaLogEntry.objects.filter(key=self).order_by('created')
+        for entry in entries:
+            timestamp = entry.created
+            delta = entry.delta
+            score = KarmaLogEntry.objects.filter(key=self).filter(created__lte=entry.created).aggregate(models.Sum('delta'))['delta__sum']
+
+            history.append((timestamp, delta, score))
+
+        return history
+
 
 class KarmaLogEntryManager(models.Manager):