What is Ruby?
Ruby is an interpreted, high-level, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan. Ruby is dynamically typed and uses garbage collection and just-in-time compilation.
What is Rubyonrails?
Ruby on Rails, or Rails, is a server-side web application framework written in Ruby under the MIT License. Rails is a model–view–controller framework, providing default structures for a database, a web service, and web pages.
Official Site : Rails
What is Jekyll?
Jekyll is a simple, blog-aware, static site generator for personal, project, or organization sites. Written in Ruby by Tom Preston-Werner, GitHub's co-founder, it is distributed under the open source MIT license.
Official Site : Jekyll