添加contest ip限制api；

OI problem的AC，total count也算入profile了

submission/migrations/0008_submission_ip.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.4 on 2017-11-10 06:57
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('submission', '0007_auto_20170923_1318'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='submission',
+            name='ip',
+            field=models.CharField(blank=True, max_length=32, null=True),
+        ),
+    ]