Box sorting field added and put into effect

boxes/models.py

@@ -41,9 +41,15 @@ class Box(models.Model):
         on_delete=models.PROTECT,
         related_name='boxes'
     )
+    sort_order = models.PositiveIntegerField(
+        default=0,
+        db_index=True,
+        help_text='Order in which boxes are displayed'
+    )
 
     class Meta:
         verbose_name_plural = 'boxes'
+        ordering = ['sort_order']
 
     def __str__(self):
         return self.id