I think the problem is in your History model you set auto_now_add=True, which will prevent your date field shown on admin, please check the django document about Model field reference:
As currently implemented, setting auto_now or auto_now_add to True will cause the field to have editable=False and blank=True set.
And about Field.editable:
If False, the field will not be displayed in the admin or any other ModelForm.
If you want it editable but also has a default value, try this:
class History(Article, IHasAttachments):
date = DateField(default=datetime.date.today)