Store subproject per change

Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/migrations/0030_change_subproject.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('trans', '0029_auto_20150415_1318'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='change',
+            name='subproject',
+            field=models.ForeignKey(to='trans.SubProject', null=True),
+        ),
+    ]

weblate/trans/models/changes.py

@@ -219,6 +219,7 @@ class Change(models.Model):
     ))
 
     unit = models.ForeignKey('Unit', null=True)
+    subproject = models.ForeignKey('SubProject', null=True)
     translation = models.ForeignKey('Translation', null=True)
     dictionary = models.ForeignKey('Dictionary', null=True)
     user = models.ForeignKey(User, null=True)