fix: loand date field cannot be null

loans/migrations/0002_alter_bookloan_loan_date.py

+# Generated by Django 5.0.7 on 2024-07-16 05:51
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('loans', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='bookloan',
+            name='loan_date',
+            field=models.DateTimeField(),
+        ),
+    ]

loans/models.py

 from django.db import models
+from django.utils import timezone
 
 from book.models import Book
 from users.models import Member
@@ -7,6 +8,6 @@ from users.models import Member
 class BookLoan(models.Model):
     book = models.OneToOneField(Book, on_delete=models.CASCADE)
     member = models.OneToOneField(Member, on_delete=models.CASCADE)
-    loan_date = models.DateTimeField(auto_now_add=True)
+    loan_date = models.DateTimeField()
     due_date = models.DateTimeField()
     return_date = models.DateTimeField(blank=True, null=True)