Added 'salable' field to Part model

InvenTree/part/migrations/0020_part_salable.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.12 on 2018-04-17 08:06
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0019_auto_20180416_1249'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='part',
+            name='salable',
+            field=models.BooleanField(default=False, help_text='Can this part be sold to customers?'),
+        ),
+    ]