Fix race condition when requesting songs, causing them to get the same order value.

marietje/queues/migrations/0004_remove_playlistsong_order.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.5 on 2017-09-23 22:59
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('queues', '0003_queuecommand'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='playlistsong',
+            name='order',
+        ),
+    ]