Language choice between JS and Ruby doesn't really matter a lot. Focus on general concepts (Http, Request/Response, Routing, Templates, model, Db, caching, orga

Language choice between JS and Ruby doesn't really matter a lot. Focus on general concepts (Http, Request/Response, Routing, Templates, model, Db, caching, organising, optimising your code, deployment, tuning). I would advise to start with some microframework (Express.js, Flask, Sinatra, whatever) to see how things really work. In Rails there's a lot of magic and you will learn Rails specific stuff instread of ungerlying techs.