cdnjs is a free distributed JS library delivery service.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Phusion Passenger is a free web server and application server with support for Ruby, Python and Node.js.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
Select2 is a jQuery based replacement for select boxes. It supports searching, remote data sets, and infinite scrolling of results.
VK is a Russian online social media and social networking service.