old_contents: from django.contrib import admin
  from subscription.models import MessageSet, Message, Subscription
  
  admin.site.register(MessageSet)
  admin.site.register(Message)
  admin.site.register(Subscription)
  
new_contents: from django.contrib import admin
  from subscription.models import MessageSet, Message, Subscription
  
  class SubscriptionAdmin(admin.ModelAdmin):
      list_display = ["contact_key", "to_addr", "message_set", "next_sequence_number",
                      "lang", "active", "completed", "created_at", "updated_at",
                      "schedule", "process_status"]
      search_fields = ["contact_key", "to_addr"]
  
  
  admin.site.register(MessageSet)
  admin.site.register(Message)
  admin.site.register(Subscription, SubscriptionAdmin)
  
subject: Add better subscription list and search admin