fix invalid scheduling

bot/cronjob/leaderboard.py

@@ -49,14 +49,11 @@ class SendLeaderboard():
         else:
             # set the message sending time; include UTC shift +2
             sending_time = time(hour=12, minute=0, second=0, tzinfo=timezone(timedelta(hours=2)))
-            job_queue.run_daily(self.callback_leaderboard, when=sending_time, day=-1)
+            job_queue.run_daily(self.callback_leaderboard, time=sending_time, days=(0))
 
 
     async def callback_leaderboard(self, context):
         """Send a weakly leaderboard to the chat."""
-        if date.today().weekday() != 1:
-            self.logger.info("Today is not Monday, skipping leaderboard.")
-            return
 
         # get the top contributions of the past week, month and year:
         ranking_week = get_author_ranking(7)