Add migration to remove school relation

Advances #115.

biscuit/core/migrations/0005_unlink_school.py

+# Generated by Django 2.2.8 on 2019-12-09 08:56
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0004_yubi_otp'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='schoolterm',
+            name='school',
+        ),
+        migrations.AlterField(
+            model_name='group',
+            name='name',
+            field=models.CharField(max_length=60, unique=True, verbose_name='Long name of group'),
+        ),
+        migrations.AlterField(
+            model_name='group',
+            name='short_name',
+            field=models.CharField(max_length=16, unique=True, verbose_name='Short name of group'),
+        ),
+        migrations.AlterField(
+            model_name='person',
+            name='import_ref',
+            field=models.CharField(blank=True, editable=False, max_length=64, null=True, unique=True, verbose_name='Reference ID of import source'),
+        ),
+        migrations.AlterField(
+            model_name='person',
+            name='short_name',
+            field=models.CharField(blank=True, max_length=5, null=True, unique=True, verbose_name='Short name'),
+        ),
+        migrations.AlterUniqueTogether(
+            name='group',
+            unique_together=set(),
+        ),
+        migrations.AlterUniqueTogether(
+            name='person',
+            unique_together=set(),
+        ),
+        migrations.RemoveField(
+            model_name='group',
+            name='school',
+        ),
+        migrations.RemoveField(
+            model_name='person',
+            name='school',
+        ),
+    ]