add models.SET_NULL for last_post

lbforum/migrations/0002_auto_20160811_0211.py

@@ -0,0 +1,26 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10 on 2016-08-11 02:11
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lbforum', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='forum',
+            name='last_post',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to='lbforum.Post', verbose_name='Last post'),
+        ),
+        migrations.AlterField(
+            model_name='topic',
+            name='last_post',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='last_post_topics', to='lbforum.Post', verbose_name='Last post'),
+        ),
+    ]

lbforum/models.py

@@ -43,8 +43,9 @@ class Forum(models.Model):
     num_topics = models.IntegerField(default=0)
     num_posts = models.IntegerField(default=0)
 
-    last_post = models.ForeignKey(  # TODO set none
-        'Post', verbose_name=_('Last post'),
+    last_post = models.ForeignKey(
+        'Post', models.SET_NULL,
+        verbose_name=_('Last post'),
         blank=True, null=True)
 
     class Meta:
@@ -116,8 +117,9 @@ class Topic(models.Model):
     created_on = models.DateTimeField(auto_now_add=True)
     updated_on = models.DateTimeField(blank=True, null=True)
     last_reply_on = models.DateTimeField(auto_now_add=True)
-    last_post = models.ForeignKey(  # TODO set none
-        'Post', verbose_name=_('Last post'),
+    last_post = models.ForeignKey(
+        'Post', models.SET_NULL,
+        verbose_name=_('Last post'),
         related_name='last_post_topics', blank=True, null=True)
 
     has_imgs = models.BooleanField(default=False)