Case insensitive Charfield in django models

I am trying to achieve a category model where name has unique=True, but practically I can still add same category name with different cases.

i.e. I have a category called Food I am still able to add food, FOOD, fOod, FOOd

Is their any philosophy behind this? or it is a work in progress.

Cause in real world if I think of Category Food, it will always be food, no matter what case it has used to mention itself.

Thank you in advance to look at this.

To answer my own question:

I have found I can have clean method on my model. So I added

class Category(models.Model):
    name = models.CharField(max_length=200, unique=True)

    def clean(self):
        self.name = self.name.capitalize()
        return super().clean()
        

It is capitalising the first letter, which is then handled by the save method, which calls the validate_unique method to raise error.