cdnjs is a free distributed JS library delivery service.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
Ruby is an open-source object-oriented programming language.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
WEBrick is a lightweight HTTP server library in Ruby, included in the standard library, primarily used for local development and testing of Ruby web applications.