reformat code

billard/migrations/0004_accounting.py

@@ -2,12 +2,11 @@
 # Generated by Django 1.10.5 on 2017-02-04 10:17
 from __future__ import unicode_literals
 
-from django.db import migrations, models
 import django.db.models.deletion
+from django.db import migrations, models
 
 
 class Migration(migrations.Migration):
-
     dependencies = [
         ('billard', '0003_client'),
     ]