django/contrib/auth/migrations/0008_alter_user_username_max_length.py

from django.contrib.auth import validators
from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('auth', '0007_alter_validators_add_error_messages'),
    ]

    operations = [
        migrations.AlterField(
            model_name='user',
            name='username',
            field=models.CharField(
                error_messages={'unique': 'A user with that username already exists.'},
                help_text='Required. 150 characters or fewer. Letters, digits and @/./+/-/_ only.',
                max_length=150,
                unique=True,
                validators=[validators.UnicodeUsernameValidator()],
                verbose_name='username',
            ),
        ),
    ]