Improve the 'creation date' for order

- Automatically set on first save

InvenTree/order/migrations/0012_auto_20190617_1943.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.2.2 on 2019-06-17 09:43
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('order', '0011_auto_20190615_1928'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='purchaseorder',
+            name='creation_date',
+            field=models.DateField(blank=True, null=True),
+        ),
+    ]

InvenTree/order/models.py

@@ -50,6 +50,12 @@ class Order(models.Model):
 
         return " ".join(el)
 
+    def save(self, *args, **kwargs):
+        if not self.creation_date:
+            self.creation_date = dateimt.now().date()
+
+        super().save(*args, **kwargs)
+
     class Meta:
         abstract = True
 
@@ -59,7 +65,7 @@ class Order(models.Model):
 
     URL = models.URLField(blank=True, help_text=_('Link to external page'))
 
-    creation_date = models.DateField(auto_now=True, editable=False)
+    creation_date = models.DateField(blank=True, null=True)
 
     status = models.PositiveIntegerField(default=OrderStatus.PENDING, choices=OrderStatus.items(),
                                          help_text='Order status')