We have the tag ruby-on-rails (7 questions) which is
... an open source full-stack web application framework written in Ruby. It follows the popular MVC framework model and is known for its "convention over configuration" approach to application development.
according to the tag wiki over on Stack Overflow.
We also have the tag ruby which happens to be the programming language used by Ruby on Rails.
What is so specific in developing solutions with the Stack Exchange API in Rails that it warrants its own tag?
Isn't calling / consuming the API in Rails the same as in a plain / simple Ruby app?
If those differences are minimal is it warranted to keep those Ruby questions spread over two tags? Does it hamper experts wanting to answer these RoR questions if they don't have a specific tag but only the ruby tag?