マイグレーション 微修正

database/migrations/2023_08_22_100200_add_column_contracts_contract_code.php

@@ -34,8 +34,6 @@ return new class extends Migration
         Schema::table('contracts', function (Blueprint $table) {
             $helper = new MigrationHelper($table);
             $table->dropColumn("contract_code");
-
-            $helper->dropIndex(1);
         });
         Schema::table('contract_histories', function (Blueprint $table) {
             $table->dropColumn("contract_code");