I was asked this question, "How do you see Object Orientation in terms of rails?". What would be a perfect answer for this in an interview?
This is an open-ended question giving you the opportunity to show your Ruby, Rails, and general OO knowledge.
I'd start by talking about the differences and constraints of Rails compared to plain Ruby which would show both your understand of Ruby's Object model and Rails' constraints and idiosyncrasies. Notably, one must talk of Single Table Inheritance and the potential problems of using it as opposed to having separate classes and tables (though one could still use inheritance in abstract classes for the business logic).
Furthermore, you could talk about how Rails works, e.g. its heavy use of delegation through proxies, though this might be going too deep, but it would show understanding of the inner workings of Rails which is needed if anything 'unusual' needs to be done.
Finally, I'd talk about design patterns, since Rails' success was harnessing many patterns and paradigms such as MVC and ActiveRecord - things we now take for granted.