diff --git a/app/controllers/content_controller.rb b/app/controllers/content_controller.rb
index 8d115431..94b4282e 100644
--- a/app/controllers/content_controller.rb
+++ b/app/controllers/content_controller.rb
@@ -508,7 +508,10 @@ class ContentController < ApplicationController
     @attribute_field = AttributeField.find_by(id: params[:field_id].to_i)
     attribute_value = @attribute_field.attribute_values.order('created_at desc').find_or_initialize_by(entity_params)
     attribute_value.user_id ||= current_user.id
-    attribute_value.value = field_params.fetch('value', '').to_i
+
+    new_universe_id = field_params.fetch('value', nil).to_i
+    new_universe_id = nil if new_universe_id == 0
+    attribute_value.value = new_universe_id
     attribute_value.save!
 
     @content = entity_params.fetch('entity_type').constantize.find_by(
diff --git a/app/models/concerns/has_changelog.rb b/app/models/concerns/has_changelog.rb
index 2d543733..5dc9eab6 100644
--- a/app/models/concerns/has_changelog.rb
+++ b/app/models/concerns/has_changelog.rb
@@ -40,6 +40,7 @@ module HasChangelog
     before_update do
       if self.is_a?(Attribute)
         # todo how to get current_user?
+
         ContentChangeEvent.create(
           user:           find_current_user,
           changed_fields: changes,
diff --git a/config/environments/development.rb b/config/environments/development.rb
index eef5b034..121334cb 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -59,6 +59,10 @@ Rails.application.configure do
   # routes, locales, etc. This feature depends on the listen gem.
   config.file_watcher = ActiveSupport::EventedFileUpdateChecker
 
+  # Whitelist HashWithIndifferentAccess/TimeWithZone for changelog serialization
+  # config.active_record.yaml_column_permitted_classes = [HashWithIndifferentAccess, ActiveSupport::TimeWithZone, Time]
+  config.active_record.use_yaml_unsafe_load = true
+
   # Set test-mode Stripe API key
   Stripe.api_key = "sk_test_v37uWbseyPct6PpsfjTa3y1l"
   config.stripe_publishable_key = 'pk_test_eXI4iyJ2gR9UOGJyJERvDlHF'
diff --git a/config/environments/production.rb b/config/environments/production.rb
index 5d65c2ce..7bd937d7 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -91,6 +91,10 @@ Rails.application.configure do
   # Do not dump schema after migrations.
   config.active_record.dump_schema_after_migration = false
 
+  # Whitelist HashWithIndifferentAccess/TimeWithZone for changelog serialization
+  # config.active_record.yaml_column_permitted_classes = [HashWithIndifferentAccess, ActiveSupport::TimeWithZone, Time]
+  config.active_record.use_yaml_unsafe_load = true
+
   # Devise default url options
   config.action_mailer.default_url_options = { host: 'www.notebook.ai' }
   config.active_job.default_url_options    = { host: 'www.notebook.ai' }