Remove redundant deleted field on Items, cleanerversion does this

for us.
Also, slugs can be a SlugField

src/pretix/base/migrations/0020_auto_20150319_1044.py

@@ -0,0 +1,74 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0019_auto_20150314_1247'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='item',
+            options={'verbose_name': 'Product', 'verbose_name_plural': 'Products'},
+        ),
+        migrations.AlterModelOptions(
+            name='itemcategory',
+            options={'ordering': ('position', 'id'), 'verbose_name': 'Product category', 'verbose_name_plural': 'Product categories'},
+        ),
+        migrations.AlterModelOptions(
+            name='itemvariation',
+            options={'verbose_name': 'Product variation', 'verbose_name_plural': 'Product variations'},
+        ),
+        migrations.AlterModelOptions(
+            name='property',
+            options={'verbose_name': 'Product property', 'verbose_name_plural': 'Product properties'},
+        ),
+        migrations.RemoveField(
+            model_name='item',
+            name='deleted',
+        ),
+        migrations.AlterField(
+            model_name='cartposition',
+            name='attendee_name',
+            field=models.CharField(null=True, help_text='Empty, if this product is not an admission ticket', verbose_name='Attendee name', max_length=255, blank=True),
+        ),
+        migrations.AlterField(
+            model_name='event',
+            name='presale_end',
+            field=models.DateTimeField(null=True, help_text='No products will be sold after this date.', verbose_name='End of presale', blank=True),
+        ),
+        migrations.AlterField(
+            model_name='event',
+            name='presale_start',
+            field=models.DateTimeField(null=True, help_text='No products will be sold before this date.', verbose_name='Start of presale', blank=True),
+        ),
+        migrations.AlterField(
+            model_name='eventpermission',
+            name='can_change_items',
+            field=models.BooleanField(default=True, verbose_name='Can change product settings'),
+        ),
+        migrations.AlterField(
+            model_name='item',
+            name='admission',
+            field=models.BooleanField(default=False, help_text='Whether or not buying this product allows a person to enter your event', verbose_name='Is an admission ticket'),
+        ),
+        migrations.AlterField(
+            model_name='item',
+            name='short_description',
+            field=models.TextField(null=True, help_text='This is shown below the product name in lists.', verbose_name='Short description', blank=True),
+        ),
+        migrations.AlterField(
+            model_name='orderposition',
+            name='attendee_name',
+            field=models.CharField(null=True, help_text='Empty, if this product is not an admission ticket', verbose_name='Attendee name', max_length=255, blank=True),
+        ),
+        migrations.AlterField(
+            model_name='organizer',
+            name='slug',
+            field=models.SlugField(verbose_name='Slug', unique=True),
+        ),
+    ]