diff --git a/db/migrate/20260426061518_add_map_url_to_schedule_items.rb b/db/migrate/20260426061518_add_map_url_to_schedule_items.rb
index c709c38..cb4bc43 100644
--- a/db/migrate/20260426061518_add_map_url_to_schedule_items.rb
+++ b/db/migrate/20260426061518_add_map_url_to_schedule_items.rb
@@ -1,5 +1,10 @@
 class AddMapUrlToScheduleItems < ActiveRecord::Migration[8.1]
   def change
-    add_column :schedule_items, :map_url, :string
+    # Idempotent: production database already has this column from a prior
+    # schema:load, but `schema_migrations` did not record this version, which
+    # caused a deploy crash loop (PG::DuplicateColumn). `if_not_exists` lets
+    # the migration succeed in that drifted state so Rails records the version
+    # and future deploys are clean.
+    add_column :schedule_items, :map_url, :string, if_not_exists: true
   end
 end