Allow longer group names.

biscuit/core/migrations/0017_group_name_length.py

+# Generated by Django 2.2.4 on 2019-09-02 19:37
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0016_parent_groups'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='group',
+            name='name',
+            field=models.CharField(max_length=60, verbose_name='Long name of group'),
+        ),
+        migrations.AlterField(
+            model_name='group',
+            name='short_name',
+            field=models.CharField(max_length=16, verbose_name='Short name of group'),
+        ),
+    ]