Some user do not have a registration date

users/models.py

@@ -4,6 +4,7 @@
 
 from django.contrib.auth.models import AbstractUser
 from django.db import models
+from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 
 from med.settings import MAX_EMPRUNT
@@ -34,6 +35,11 @@ class User(AbstractUser):
         max_length=255,
         blank=True,
     )
+    date_joined = models.DateTimeField(
+        _('date joined'),
+        default=timezone.now,
+        null=True,
+    )
 
     REQUIRED_FIELDS = ['first_name', 'last_name', 'email']