如何在Rails中创建用户可自定义的数据库（如Zoho创建者）？

I'm learning Rails, and the target of my experiments is to realize something similar to Zoho Creator, Flexlist or Mytaskhelper, i.e. an app where the user can create his own database schema and views. What's the best strategy to pursue this?I'm learning Rails, and the target of my experi