Add 'reference' field to BOM item model

InvenTree/part/migrations/0012_auto_20190627_2144.py

@@ -0,0 +1,23 @@
+# Generated by Django 2.2.2 on 2019-06-27 11:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0011_part_revision'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='bomitem',
+            name='reference',
+            field=models.CharField(blank=True, help_text='BOM item reference', max_length=500),
+        ),
+        migrations.AlterField(
+            model_name='bomitem',
+            name='note',
+            field=models.CharField(blank=True, help_text='BOM item notes', max_length=500),
+        ),
+    ]