new_contents: # Generated by Django 2.2.5 on 2019-09-27 16:16
  
  from django.db import migrations, models
  import django.db.models.deletion
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('package', '0004_auto_20180214_0617'),
      ]
  
      operations = [
          migrations.AlterField(
              model_name='package',
              name='category',
              field=models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, to='package.Category', verbose_name='Installation'),
          ),
      ]
  
subject: Add migrations that protects packages on category deletion