[ghostdiver]

It's bad idea to "stick to that one", no benefit, it will only decrease chances of getting some gig/contract. Since you are aiming for established bigger companies, expect to work on some outdated technologies. Ruby/nodejs is not outdated yet, it might as well cease to exist in few years, because very few businesses will manage to establish on such technologies.

[Leander_B]

Not too sure. Considering the limited timeframe and wanting to get ready for employment, I think it's the correct decision to stick to one and get good enough in it rather than learning more technologies and not being able to work with any proficiently. Compare it to the bootcamps which usually also only stick to one language. (I will teach her HTML CSS and jQuery, but this is not included in the 4-5 months of learning a programming language.)