add migration

lists/migrations/0004_remove_duplicates.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.24 on 2019-12-10 16:01
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+def find_dupes(apps, schema_editor):
+    List = apps.get_model("lists", "List")
+    for list_ in List.objects.all():
+        items = list_.item_set.all()
+        texts = set()
+        for ix, item in enumerate(items):
+            if item.text in texts:
+                item.text = '{} ({})'.format(item.text, ix)
+                item.save()
+            texts.add(item.text)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lists', '0003_auto_20191121_1714'),
+    ]
+
+    operations = [
+        migrations.RunPython(find_dupes),
+    ]