I need to patch the standard User model of contrib.auth by ensuring the email field entry is unique:
contrib.auth
User._meta.fields[4].unique = True <
User._meta.fields[4].unique = True
In settings module:
# Fix: username length is too small,email must be unique from django.contrib.auth.models import User, models User._meta.local_fields[1].__dict__['max_length'] = 75 User._meta.local_fields[4].__dict__['_unique'] = True