mail: add default order, by postal or creation date (#14824)

welco/sources/mail/migrations/0011_mail_reference.py

@@ -16,4 +16,9 @@ class Migration(migrations.Migration):
             name='reference',
             field=models.CharField(max_length=30, null=True, verbose_name='Reference'),
         ),
+        migrations.AlterModelOptions(
+            name='mail',
+            options={'ordering': ['creation_timestamp', 'post_date'],
+                     'verbose_name': 'Mail'},
+        ),
     ]

welco/sources/mail/models.py

@@ -35,6 +35,7 @@ class Mail(models.Model):
 
     class Meta:
         verbose_name = _('Mail')
+        ordering = ['creation_timestamp', 'post_date']
 
     content = models.FileField(_('Content'))
     post_date = models.DateField(_('Post Date'), null=True)