add lock events

db/migrate/20250915060548_create_lock_events.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class CreateLockEvents < ActiveRecord::Migration[8.0]
+  def change
+    create_table :lock_events do |t|
+      t.string :key, index: true, null: false
+      t.string :event_name, null: false
+
+      t.index %i[event_name key], unique: true, where: "event_name IN ('start', 'complete')"
+
+      t.timestamps
+    end
+  end
+end