From f6c3ceee40917129cadbedc1cb9d13a5a943e0d2 Mon Sep 17 00:00:00 2001
From: virusdefender <1670873886@qq.com>
Date: Wed, 12 Aug 2015 22:59:05 +0800
Subject: [PATCH] =?UTF-8?q?=E5=88=A0=E9=99=A4=20ManyToMany=20=E5=AD=97?=
 =?UTF-8?q?=E6=AE=B5=E6=97=A0=E6=95=88=E7=9A=84=20null=3DTrue?=
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---
 problem/migrations/0004_auto_20150812_2254.py | 19 +++++++++++++++++++
 problem/models.py                             |  2 +-
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 problem/migrations/0004_auto_20150812_2254.py

diff --git a/problem/migrations/0004_auto_20150812_2254.py b/problem/migrations/0004_auto_20150812_2254.py
new file mode 100644
index 0000000..75f85d4
--- /dev/null
+++ b/problem/migrations/0004_auto_20150812_2254.py
@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('problem', '0003_auto_20150810_2233'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='problem',
+            name='tags',
+            field=models.ManyToManyField(to='problem.ProblemTag'),
+        ),
+    ]
diff --git a/problem/models.py b/problem/models.py
index b9a3181..aaa5ce0 100644
--- a/problem/models.py
+++ b/problem/models.py
@@ -49,4 +49,4 @@ class Problem(AbstractProblem):
     # 难度 0 - n
     difficulty = models.IntegerField()
     # 标签
-    tags = models.ManyToManyField(ProblemTag, null=True)
+    tags = models.ManyToManyField(ProblemTag)