TMSS-162: make user nullable (for fixtures)

SAS/TMSS/src/tmss/tmssapp/migrations/0001_initial.py

@@ -527,11 +527,11 @@ class Migration(migrations.Migration):
                 ('tags', django.contrib.postgres.fields.ArrayField(base_field=models.CharField(max_length=128), blank=True, default=list, help_text='User-defined search keywords for object.', size=8)),
                 ('created_at', models.DateTimeField(auto_now_add=True, help_text='Moment of object creation.')),
                 ('updated_at', models.DateTimeField(auto_now=True, help_text='Moment of last object update.')),
-                ('user_identifier', models.CharField(editable=False, help_text='The ID of the user who changed the state of the subtask.', max_length=128)),
+                ('user_identifier', models.CharField(editable=False, help_text='The ID of the user who changed the state of the subtask.', null=True, max_length=128)),
                 ('new_state', models.ForeignKey(editable=False, help_text='Subtask state after update (see Subtask State Machine).', on_delete=django.db.models.deletion.PROTECT, related_name='is_new_state_of', to='tmssapp.SubtaskState')),
                 ('old_state', models.ForeignKey(editable=False, help_text='Subtask state before update (see Subtask State Machine).', null=True, on_delete=django.db.models.deletion.PROTECT, related_name='is_old_state_of', to='tmssapp.SubtaskState')),
                 ('subtask', models.ForeignKey(editable=False, help_text='Subtask to which this state change refers.', on_delete=django.db.models.deletion.CASCADE, to='tmssapp.Subtask')),
-                ('user', models.ForeignKey(editable=False, help_text='The user who changed the state of the subtask.', on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL)),
+                ('user', models.ForeignKey(editable=False, help_text='The user who changed the state of the subtask.', null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL)),
             ],
             options={
                 'abstract': False,

SAS/TMSS/src/tmss/tmssapp/models/scheduling.py

@@ -205,8 +205,8 @@ class SubtaskStateLog(BasicCommon):
     available to keep track of changes more generally: https://djangopackages.org/grids/g/model-audit/
     This seems a bit overkill at the moment and we have to manage access to those logs etc., this needs tbd.
     """
-    user = ForeignKey(User, null=False, editable=False, on_delete=PROTECT, help_text='The user who changed the state of the subtask.')
-    user_identifier = CharField(null=False, editable=False, max_length=128, help_text='The ID of the user who changed the state of the subtask.')
+    user = ForeignKey(User, null=True, editable=False, on_delete=PROTECT, help_text='The user who changed the state of the subtask.')
+    user_identifier = CharField(null=True, editable=False, max_length=128, help_text='The ID of the user who changed the state of the subtask.')
     subtask = ForeignKey('Subtask', null=False,  editable=False, on_delete=CASCADE, help_text='Subtask to which this state change refers.')
     old_state = ForeignKey('SubtaskState', null=True,  editable=False, on_delete=PROTECT, related_name='is_old_state_of', help_text='Subtask state before update (see Subtask State Machine).')
     new_state = ForeignKey('SubtaskState', null=False, editable=False, on_delete=PROTECT, related_name='is_new_state_of', help_text='Subtask state after update (see Subtask State Machine).')