Case insensitive unique model fields in Django?

Question

I have basically a username is unique (case insensitive), but the case matters when displaying as provided by the user.

I have the following requirements:

Answer 1

As of Django 1.11, you can use CITextField, a Postgres-specific Field for case-insensitive text backed by the citext type.

from django.db import models
from django.contrib.postgres.fields import CITextField

class Something(models.Model):
    foo = CITextField()

Django also provides CIEmailField and CICharField, which are case-insensitive versions of EmailField and CharField.