Ruby on rails Rails说我有x个挂起的迁移运行`rake db:migrate`

在我的mountable_engine/test/dummy/config中的database.yml中，我为dummy app指定了一个数据库，为mountable engine指定了一个数据库：

development:
  <<: *default
  database: dummy_development

internal:
  <<: *default
  database: mountable_engine_development

当我跑的时候

rake db:random:load RAILS_ENV=internal

从命令行中，我得到以下错误：

You have 12 pending migrations:
  20150406190542 CreateTable1
  20150406201954 CreateTable2
  20150406202157 CreateTable3
  ...
  20150430225339 AddIndexToForeignKeys
Run `rake db:migrate` to update your database then try again.

我以前已经运行过迁移。现在，当我查看可装载引擎开发数据库中的模式迁移时，我可以看到迁移是最新的：

mysql> SELECT * FROM schema_migrations;
+----------------+
| version        |
+----------------+
| 20150406190542 |
| 20150406201954 |
| 20150406202157 |
| 20150406202339 |
| 20150406202535 |
| 20150406202550 |
| 20150408194521 |
| 20150411010854 |
| 20150413162723 |
| 20150413213522 |
| 20150416013325 |
| 20150430225339 |
+----------------+

---

那么为什么会出现此错误？

问题是我在可装载引擎的目录中运行rake任务。当我在虚拟应用程序的目录中运行rake任务时，它就工作了

mysql> SELECT * FROM schema_migrations;
+----------------+
| version        |
+----------------+
| 20150406190542 |
| 20150406201954 |
| 20150406202157 |
| 20150406202339 |
| 20150406202535 |
| 20150406202550 |
| 20150408194521 |
| 20150411010854 |
| 20150413162723 |
| 20150413213522 |
| 20150416013325 |
| 20150430225339 |
+----------------+