old_contents: from django.contrib import admin
  from .models import Note, Wine, Winery
  
  admin.site.register(Note)
  admin.site.register(Wine)
  admin.site.register(Winery)
new_contents: from django.contrib import admin
  from .models import Note, Trait, Wine, Winery
  
  admin.site.register(Note)
  admin.site.register(Trait)
  admin.site.register(Wine)
  admin.site.register(Winery)
subject: Add Trait model to admin page.