Fix migrations

assets/migrations/0020_auto_20210302_1201.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.1.7 on 2021-03-02 12:01
+
+from django.db import migrations
+
+
+def postgres_migration_prep(apps, schema_editor):
+    model = apps.get_model("assets", "Supplier")
+    fields = ["address", "email", "notes", "phone"]
+    for field in fields:
+        filter_param = {"{}__isnull".format(field): True}
+        update_param = {field: ""}
+        model.objects.filter(**filter_param).update(**update_param)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('assets', '0019_fix_cabletype'),
+    ]
+
+    operations = [
+        migrations.RunPython(postgres_migration_prep, migrations.RunPython.noop)
+    ]

assets/migrations/0021_auto_20210302_1204.py

@@ -1,4 +1,4 @@
-# Generated by Django 3.1.5 on 2021-02-08 16:03
+# Generated by Django 3.1.7 on 2021-03-02 12:04
 
 from django.db import migrations, models
 import django.db.models.deletion
@@ -7,7 +7,7 @@ import django.db.models.deletion
 class Migration(migrations.Migration):
 
     dependencies = [
-        ('assets', '0019_fix_cabletype'),
+        ('assets', '0020_auto_20210302_1201'),
     ]
 
     operations = [
@@ -20,12 +20,14 @@ class Migration(migrations.Migration):
         migrations.AlterField(
             model_name='cabletype',
             name='plug',
-            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='plug', to='assets.connector'),
+            field=models.ForeignKey(default=1, on_delete=django.db.models.deletion.CASCADE, related_name='plug', to='assets.connector'),
+            preserve_default=False,
         ),
         migrations.AlterField(
             model_name='cabletype',
             name='socket',
-            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='socket', to='assets.connector'),
+            field=models.ForeignKey(default=1, on_delete=django.db.models.deletion.CASCADE, related_name='socket', to='assets.connector'),
+            preserve_default=False,
         ),
         migrations.AlterField(
             model_name='supplier',