diff --git a/account/migrations/0004_auto_20150806_1251.py b/account/migrations/0004_auto_20150806_1251.py
new file mode 100644
index 0000000..d3d2225
--- /dev/null
+++ b/account/migrations/0004_auto_20150806_1251.py
@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('account', '0003_user_email'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='user',
+            name='admin_group',
+        ),
+        migrations.AddField(
+            model_name='user',
+            name='admin_type',
+            field=models.IntegerField(default=0),
+        ),
+    ]
diff --git a/announcement/migrations/0001_initial.py b/announcement/migrations/0001_initial.py
index 24a1d13..7e8d583 100644
--- a/announcement/migrations/0001_initial.py
+++ b/announcement/migrations/0001_initial.py
@@ -17,8 +17,9 @@ class Migration(migrations.Migration):
             fields=[
                 ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
                 ('title', models.CharField(max_length=50)),
-                ('description', models.TextField()),
+                ('content', models.TextField()),
                 ('create_time', models.DateTimeField(auto_now_add=True)),
+                ('last_update_time', models.DateTimeField(auto_now=True)),
                 ('visible', models.BooleanField(default=True)),
                 ('created_by', models.ForeignKey(to=settings.AUTH_USER_MODEL)),
             ],
diff --git a/announcement/migrations/0002_auto_20150806_1104.py b/announcement/migrations/0002_auto_20150806_1104.py
deleted file mode 100644
index 2768cc6..0000000
--- a/announcement/migrations/0002_auto_20150806_1104.py
+++ /dev/null
@@ -1,19 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import models, migrations
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('announcement', '0001_initial'),
-    ]
-
-    operations = [
-        migrations.RenameField(
-            model_name='announcement',
-            old_name='description',
-            new_name='content',
-        ),
-    ]
diff --git a/announcement/models.py b/announcement/models.py
index a3574b8..491c219 100644
--- a/announcement/models.py
+++ b/announcement/models.py
@@ -13,6 +13,8 @@ class Announcement(models.Model):
     create_time = models.DateTimeField(auto_now_add=True)
     # 这个公告是谁创建的
     created_by = models.ForeignKey(User)
+    # 最后更新时间
+    last_update_time = models.DateTimeField(auto_now=True)
     # 是否可见 false的话相当于删除
     visible = models.BooleanField(default=True)