Updating Category table the right way, typos

~A cleaner , more understandable way to updating the Category table with a SlugField while staying clean from the UNIQUE constraint failed error.

~Fixed code not showing up.
~Fixed Indentation.

I'm not sure about it , but shouldn't SlugField have a max_length=128, i mean since it inherits its value from the name field, and the SlugField has a default max_length=50.

#Docs say:
class SlugField([max_length=50, **options])