At this point in your career, I would be concerned with two things:
1. Differentiating yourself from other entry-level candidates when you graduate a year from now. The best way to do this is simply to built-out your portfolio. Launch as many real sites and apps as you can...in whatever language/stack makes sense for the app in question.
2. Finding something you really enjoy. If you love building RoR sites, great! But if you think pursuing A.I. and such might make you happier in the long run, then you should pursue that path. At the end of the day, finding a sub-field that really interests you will make your career go a lot smoother.
Time is on your side. You've got plenty of options, and I would recommend you pursue any and all of the ones that you find interesting.