Fix validation of unique_process_run_slug constraint in the Django admin

arkindex/ponos/migrations/0002_task_process.py

@@ -48,7 +48,7 @@ class Migration(migrations.Migration):
         migrations.AddConstraint(
             model_name='task',
             constraint=models.UniqueConstraint(
-                models.F('process_id'),
+                models.F('process'),
                 models.F('run'),
                 models.F('slug'),
                 name='unique_process_run_slug',

arkindex/ponos/models.py

@@ -451,7 +451,7 @@ class Task(models.Model):
         ordering = ("process_id", "run", "depth", "slug")
         constraints = [
             models.UniqueConstraint(
-                'process_id',
+                'process',
                 'run',
                 'slug',
                 name='unique_process_run_slug',