Add the cof_members group

GestioCOF cannot run without it.
There is no permission associated to it: this has to been thought about

cof/migrations/0011_create_cof_group.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+def create_cof_group(apps, schema_editor):
+    Group = apps.get_model("auth", "Group")
+    Group.objects.get_or_create(name="cof_members")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cof', '0010_remove_cofprofile_is_cof'),
+    ]
+
+    operations = [
+        migrations.RunPython(create_cof_group, migrations.RunPython.noop)
+    ]