Django model convert IntegerField to ForeingKey keeping date

I'm working in a project where I need to migrate an IntegerField to a ForeingKey to make it easier to do requests as: SKU_name, SKU_description, etc..

My models.py file has:

class BasketTable(models.Model):
    """Basket table."""

    SKU_Id = models.IntegerField(default=0, verbose_name="ID do SKU")
    Quantity = models.IntegerField(default=0, verbose_name="Quantidade")

I'm trying to change SKU_Id to SKU field name, setting:

SKU = models.ForeignKey(SKUTable, db_column='Id', to_field='Id', null=True, verbose_name="ID do SKU")

My SKU_Id field has unique=True as needed according Django documentation.

So, after this change, I run python manage.py makemigrations command which results in:

class Migration(migrations.Migration):

    dependencies = [
    ]

    operations = [
        migrations.RemoveField(
            model_name='baskettable',
            name='SKU_Id',
        ),
        migrations.AddField(
            model_name='baskettable',
            name='SKU',
            field=models.ForeignKey(db_column='Id', null=True, on_delete=django.db.models.deletion.CASCADE, to='products.SKUTable', to_field='Id', verbose_name='ID do SKU'),
        ),
    ]

So, I changed this migration file to:

class Migration(migrations.Migration):

    dependencies = [
    ]

    operations = [
        migrations.AlterField(
            model_name='baskettable',
            name='SKU_Id',
            field=models.IntegerField(db_column='Id')
        ),
        migrations.RenameField(
            model_name='baskettable',
            old_name='SKU_Id',
            new_name='SKU',
        ),
        migrations.AlterField(
            model_name='baskettable',
            name='SKU',
            field=models.ForeignKey(db_column='Id', null=True, on_delete=django.db.models.deletion.CASCADE,
                                    to='products.SKUTable', to_field='Id', verbose_name='ID do SKU'),
        ),
    ]

And after this, I run the command python manage.py migrate to save these changes.

The migration works and the data SKU and SKU_id can be accessed using list_display in my Admin, but when I try to access data as SKU_name or any other field, I got this error message:

SystemCheckError: SystemCheckError: System check identified some issues:

ERRORS:
<class 'cil.models.BasketTableAdmin'>: (admin.E108) The value of 'list_display[0]' refers to 'SKU_Name', which is not a callable, an attribute of 'BasketTableAdmin', or an attribute or method on 'cil.BasketTable'.

System check identified 1 issue (0 silenced).

I hope that someone can make clear what I'm doing wrong when I try to get other table fields using the list_display or any other get function from models.

I used the following information to get here:

http://www.probthink.com/tech/converting-an-integer-id-field-to-foreign-key-field-without-data-migration/

https://docs.djangoproject.com/en/1.11/ref/models/fields/#django.db.models.ForeignKey.to_field

Edit 1:

I cleaned the code a little bit more.

One possible solution that I found is not change the name of the field and don't use db_column, instead, use to_field='destination_key_field'.

SKU = models.ForeignKey(SKUTable, to_field='Id', null=True, verbose_name="ID do SKU")

It is important to have null=True when working with this change.