cdnjs is a free distributed JS library delivery service.
Google Maps is a web mapping service. It offers satellite imagery, aerial photography, street maps, 360° interactive panoramic views of streets, real-time traffic conditions, and route planning for traveling by foot, car, bicycle and air, or public transportation.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
RackCache is a quick drop-in component to enable HTTP caching for Rack-based applications.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.