extend the admin interface for the order class

In order to be able to correctly edit the an order we need the
information of the induvidual order positions. In addition a better
layout is required to better find the information.

django/didgeridoo/webshop/admin.py

@@ -3,8 +3,8 @@ from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
 from django.contrib.auth.models import User
 
 # Register your models here.
-from .models import (Article, Order, Person, City, Picture, OrderOfGoods,
-                     Category, Option, Setting)
+from .models import (Article, Order, OrderPosition, Person, City, Picture,
+                     OrderOfGoods, Category, Option, Setting)
 
 
 class PersonInline(admin.StackedInline):
@@ -17,11 +17,25 @@ class UserAdmin(BaseUserAdmin):
     inlines = (PersonInline,)
 
 
+class OrderPositionInline(admin.StackedInline):
+    model = OrderPosition
+    can_delete = False
+    verbose_name_plural = 'Order Positions'
+
+
+class OrderAdmin(admin.ModelAdmin):
+    list_display = ('id', 'user', 'date')
+    list_filter = ('date',)
+    date_hierarchy = 'date'
+    ordering = ('-date',)
+    inlines = (OrderPositionInline,)
+
+
 admin.site.unregister(User)
 admin.site.register(User, UserAdmin)
 
 admin.site.register(Article)
-admin.site.register(Order)
+admin.site.register(Order, OrderAdmin)
 admin.site.register(City)
 admin.site.register(Picture)
 admin.site.register(OrderOfGoods)