Format date for db

app.py

@@ -74,7 +74,7 @@ def toggle_pin(change_pin):
         if pins[change_pin]['on_time'] is not None:
             start_time = pins[change_pin]['on_time']
             elapsed = str(datetime.now() - start_time)
-            start_date = datetime.strptime(str(start_time), '%Y-%m-%d').date()
+            start_date = datetime.strftime(start_time, '%Y-%m-%d').date()
             entry = DailyUsage(date=start_date, on_time=elapsed)
             db.session.add(entry)
             db.session.commit()