Konstantin Gredeskoul (CTO, Wanelo) has been building and deploying large-scale distributed software into production for more than a decade. Having inherited a java-based web app which was gaining rapid popularity with users and having a difficult time scaling, Konstantin successfully lead the team @ Wanelo in rewriting the entire app from scratch. The team chose ruby on rails, and accomplished the switch in only two months with six engineers, all the while migrating data from MySQL to PostgreSQL.