Google検索（Mountable Engine）

- Mountable Engine だらけの Rails アプリ開発
http://blog.onk.ninja/2014/12/02/mountable_engi...
- Spree
https://github.com/spree/spree
- RefineryCMS
https://github.com/refinery/refinerycms
- Rails エンジン入門 — Rails ガイド
http://railsguides.jp/engines.html

- How can I create a concern in a Rails engine?
http://stackoverflow.com/questions/14218223/how...
- Building Mountable Apps
http://www.neotericdesign.com/blog/2012/4/build...
- using ActiveSupport::Concerns to extend Rails
https://gist.github.com/daemianmack/3151794

- ruffnote/freeplus-hotels
https://github.com/ruffnote/freeplus-hotels
（該当部分をEngine化した時のサンプル）
https://github.com/ruffnote/freeplus/pull/519
- ruffnote/freeplus-timecards
https://github.com/ruffnote/freeplus-timecards
（サブディレクトリまで読み込むサンプル）
https://github.com/ruffnote/freeplus-timecards/...
- ruffnote/freeplus-issues
https://github.com/ruffnote/freeplus-issues/com...

https://ruffnote.com/akikumo_tea/dynamic-scaffo...