Add nickname field to assets

So we can stop storing nicknames in the sodding serial number

assets/migrations/0011_asset_nickname.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.0.13 on 2020-03-02 17:53
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('assets', '0010_auto_20200207_1737'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='asset',
+            name='nickname',
+            field=models.CharField(blank=True, max_length=20, unique=True),
+        ),
+    ]