Add UUID field to StockItem model

InvenTree/stock/migrations/0006_stockitem_uuid.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.2 on 2019-04-12 15:06
+
+from django.db import migrations, models
+import uuid
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0005_stockitemtracking_quantity'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='stockitem',
+            name='uuid',
+            field=models.UUIDField(blank=True, default=uuid.uuid4, editable=False),
+        ),
+    ]