The backend of Salon is implemented in Ruby on Rails (short Rails), a web framework written in Ruby (Ruby is a object-oriented programming language with a dynamic type system) and modeled after the MVC software pattern [MFGUIA2006] that allows to quickly create solid web applications without having to care about low-level problems like session-handling or database access. The underlying database is MongoDB (http://www.mongodb.org/), a document-oriented database system that was chosen because of its flexibility (document-oriented databases are schema free [EHCASS2011]) and its very good integration in Rails. Salon does not make use of the full Rails stack and especially the frontend toolchain is completely ignored because the frontend is designed to work as a Single Page Web App (see II 1.1). The communication between the frontend and the backend is realized with a REST(REST stands for Representational State Transfer and is an architecture style that is very efficient by making extensive use of HTTP and its methods [RFARCH2000]) interface and all data is being sent in the JSON (http://en.wikipedia.org/wiki/JavaScript_Object_Notation) format, a format that is very easy to use in both JavaScript (frontend) and Ruby (backend).