Changes PriceHistory unique together.

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>

backyard/inventory/migrations/0003_auto_20160822_2146.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10 on 2016-08-22 21:46
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('inventory', '0002_auto_20160725_1254'),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name='pricehistory',
+            unique_together=set([('product', 'registered_date', 'shop')]),
+        ),
+    ]

backyard/inventory/models/price_history.py

@@ -24,7 +24,7 @@ class PriceHistory(BaseHistory):
 
     class Meta(object):
         """Meta data."""
-        unique_together = ('product', 'registered_date')
+        unique_together = ('product', 'registered_date', 'shop')
 
     def __str__(self):
         return '{0} {1}'.format(self.product, self.price)