Add 'comment' field to part attachment model

InvenTree/part/migrations/0012_partattachment_comment.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.2 on 2019-04-28 12:31
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0011_auto_20190428_0841'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='partattachment',
+            name='comment',
+            field=models.CharField(blank=True, help_text='File comment', max_length=100),
+        ),
+    ]