Store the job's project refresh if it happened

* Create a field on the job to track this
* Add a summarizeable model to the summarizable fk fields so we can
  pull that in where needed

awx/main/migrations/0051_v310_job_project_update.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0050_v310_JSONField_changes'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='job',
+            name='project_update',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.SET_NULL, default=None, blank=True, to='main.ProjectUpdate', help_text='The SCM Refresh task used to make sure the playbooks were available for the job run', null=True),
+        ),
+    ]