added new fields to KyuDanRanking that allow to pick up the calculation from the last state of the KyuDanRanking.

last_hanchan_date: it contains the start of the latest hanchan content for this players ranking.
wins_in_row: to save the currents wins in a row

Added option to calcuclate rankings until a given datetime.

src/mahjong_ranking/tests.py

@@ -34,7 +34,7 @@ class KyuDanTest(TestCase):
 
         for ranking in KyuDanRanking.objects.all():
             original = {a: getattr(ranking, a) for a in self.equal_attrs}
-            ranking.recalculate()
+            ranking.calculate()
             for attr in self.equal_attrs:
                 self.assertEqual(
                     original[attr],
@@ -62,7 +62,7 @@ class KyuDanTest(TestCase):
                 continue
             rnd = random.randrange(confirmed_hanchans.count())
             since = confirmed_hanchans[rnd].start
-            ranking.recalculate(hanchan_start=since)
+            ranking.calculate(since=since)
             for attr in self.equal_attrs:
                 self.assertEqual(
                     original[attr],