Below you find a set of charts demonstrating the paths that you can take and the technologies that you would want to adopt in order to become a frontend, backend or a devops. I made these charts for an old professor of mine who wanted something to share with his college students to give them a perspective.
If you think that these can be improved in anyway, please do suggest.
🎨 Frontend Roadmap
👽 Backend Roadmap
For the backend, personally I would prefer Node JS and PHP-7 for the full time plus I have been experimenting lately with Go and I quite like it. Apart from these, if I have to choose another one, I would go for Ruby. However this is just my personal preference, you can choose any of the shown languages and you will be good.
👷 DevOps Roadmap