Add search to subscription admin

payments/admin.py

@@ -68,6 +68,7 @@ class SubscriptionAdmin(admin.ModelAdmin):
     readonly_fields = ('user_link', 'backend', 'period', 'created', 'status',
                        'last_confirmed_payment', 'payments_links',
                        'backend_extid_link', 'backend_data')
+    search_fields = ('user__username', 'user__email', 'backend_extid', 'backend_data')
     actions = (subscr_mark_as_cancelled,)
     fieldsets = (
         (None, {