recalculating only the new hanchans shoud do the trick now.

the racalc cronjob reports erronous partly recalculations now.
A lot of code cleanups

src/mahjong_ranking/views.py

@@ -188,9 +188,11 @@ class SeasonRankingList(MahjongMixin, generic.ListView):
 
 class PlayerScore(LoginRequiredMixin, generic.ListView):
     paginate_by = 25
+    user = auth.get_user_model()
 
     def get(self, request, *args, **kwargs):
         user_model = auth.get_user_model()
+        username = kwargs.get('username')
         try:
             self.user = user_model.objects.get(
                 username=self.kwargs.get('username'))