change migration to allow blank inventory field

awx/main/migrations/0014_v300_job_prompt_for_fields.py

@@ -2,6 +2,7 @@
 from __future__ import unicode_literals
 
 from django.db import migrations, models
+import django.db.models.deletion
 from django.conf import settings
 
 
@@ -32,4 +33,14 @@ class Migration(migrations.Migration):
             name='ask_tags_on_launch',
             field=models.BooleanField(default=False),
         ),
+        migrations.AlterField(
+            model_name='job',
+            name='inventory',
+            field=models.ForeignKey(related_name='jobs', on_delete=django.db.models.deletion.SET_NULL, default=None, blank=True, to='main.Inventory', null=True),
+        ),
+        migrations.AlterField(
+            model_name='jobtemplate',
+            name='inventory',
+            field=models.ForeignKey(related_name='jobtemplates', on_delete=django.db.models.deletion.SET_NULL, default=None, blank=True, to='main.Inventory', null=True),
+        ),
     ]

awx/main/models/jobs.py

@@ -53,7 +53,9 @@ class JobOptions(BaseModel):
     inventory = models.ForeignKey(
         'Inventory',
         related_name='%(class)ss',
+        blank=True,
         null=True,
+        default=None,
         on_delete=models.SET_NULL,
     )
     project = models.ForeignKey(