Added URL field to stock item

InvenTree/stock/migrations/0008_stockitem_url.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11 on 2018-04-16 11:05
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0007_auto_20180416_0853'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='stockitem',
+            name='URL',
+            field=models.URLField(blank=True, max_length=125),
+        ),
+    ]