old_contents: from django.contrib import admin
  from accounts.models import UserProfile
  
  class UserProfileAdmin(admin.ModelAdmin):
      list_display = ('user', 'instrument')
      ordering = ('instrument',)
  
  admin.site.register(UserProfile, UserProfileAdmin)
  
new_contents: from django.contrib import admin
  from accounts.models import UserProfile
  
  class UserProfileAdmin(admin.ModelAdmin):
      list_display = ('user',)
  
  admin.site.register(UserProfile, UserProfileAdmin)
  
subject: update admin too