Box sorting field added and put into effect

boxes/admin.py

@@ -1,3 +1,4 @@
+from adminsortable2.admin import SortableAdminMixin
 from django import forms
 from django.contrib import admin
 from django.contrib.admin import SimpleListFilter
@@ -13,7 +14,7 @@ class BoxFilter(SimpleListFilter):
     parameter_name = 'box__pk'
 
     def lookups(self, request, model_admin):
-        boxes = Box.objects.select_related('box_type').order_by('id')
+        boxes = Box.objects.select_related('box_type').order_by('sort_order')
         return [(box.pk, str(box)) for box in boxes]
 
     def queryset(self, request, queryset):
@@ -47,7 +48,7 @@ class BoxTypeAdmin(admin.ModelAdmin):
 
 
 @admin.register(Box)
-class BoxAdmin(admin.ModelAdmin):
+class BoxAdmin(SortableAdminMixin, admin.ModelAdmin):
     """Admin configuration for Box model."""
 
     list_display = ('id', 'box_type')

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

boxes/views.py

@@ -79,7 +79,7 @@ def edit_thing(request, thing_id):
         pk=thing_id
     )
 
-    boxes = Box.objects.select_related('box_type').all().order_by('id')
+    boxes = Box.objects.select_related('box_type').all()
     facets = Facet.objects.all().prefetch_related('tags')
     picture_form = ThingPictureForm(instance=thing)
     file_form = ThingFileForm()
@@ -192,7 +192,7 @@ def edit_thing(request, thing_id):
 @login_required
 def boxes_list(request):
     """Boxes list page showing all boxes with contents."""
-    boxes = Box.objects.select_related('box_type').prefetch_related('things').all().order_by('id')
+    boxes = Box.objects.select_related('box_type').prefetch_related('things').all()
     return render(request, 'boxes/boxes_list.html', {
         'boxes': boxes,
     })