add is first to completed submitters

db/migrate/20251121092044_add_is_first_to_completed_submitters.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class AddIsFirstToCompletedSubmitters < ActiveRecord::Migration[8.0]
+  def change
+    # rubocop:disable Rails/ThreeStateBooleanColumn
+    add_column :completed_submitters, :is_first, :boolean
+    # rubocop:enable Rails/ThreeStateBooleanColumn
+
+    add_index :completed_submitters, %i[account_id completed_at], where: 'is_first = TRUE'
+    add_index :completed_submitters, :submission_id, unique: true, where: 'is_first = TRUE'
+  end
+end