Link persons to users.

biscuit/core/migrations/0009_person_user.py

+# Generated by Django 2.2.3 on 2019-07-30 20:29
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('core', '0008_school_person_group'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='person',
+            name='user',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL,
+                                    related_name='person', to=settings.AUTH_USER_MODEL),
+        ),
+    ]

biscuit/core/models.py

+from django.contrib.auth import get_user_model
 from django.db import models
 from django.utils.translation import gettext_lazy as _
 
@@ -21,6 +22,9 @@ class Person(SchoolRelated):
         ('m', _('male'))
     ]
 
+    user = models.ForeignKey(
+        get_user_model(), on_delete=models.SET_NULL, blank=True, null=True,
+        related_name='person')
     is_active = models.BooleanField(
         verbose_name=_('Is person active?'), default=False)