auto_now_add fields override my input

From the docs:

The auto_now and auto_now_add options will always use the date in the default timezone at the moment of creation or update. If you need something different, you may want to consider simply using your own callable default or overriding save() instead of using auto_now or auto_now_add; or using a DateTimeField instead of a DateField and deciding how to handle the conversion from datetime to date at display time.

So you should do that instead

bar = models.DateTimeField(default=date.today)