RoR is cool but it narrows down your career opportunities. I would learn a modern mainstream language as well, e.g. Scala or C#, they can be used outside of scope of small/medium size web apps.
That is not good advice. Ruby on Rails is widely used. Java would be a good option, but it would probably not be something that could be picked up as easily or as quickly as something with RoR, Python, PHP or JavaScript. C# would narrow your options much more because it would lock you into the proprietary MS world. Something with iOS or Android would be preferable. Note: I'm not saying C# is bad, I have used it and w…
Actually C# is the best option if you want to cover both iOS and Android.