You should be able to use your newfound skillset to integrate your frontends with either Ruby on Rails or NodeJS - the backends Odin teaches. However, in fact, your frontend can integrate with any back-end technologies under the right circumstances! After all, you’ve spent time working with APIs from the frontend already!
If you find something you don’t know or aren’t sure about, you should be, by now, a pro at Googling your way to an answer, looking at docs, and cruising through Stack Overflow posts. You’ve got all the tools you need to be a developer. And, really, the big secret is that you’ve been a web developer for some time already.
There’s a whole world of exciting things you can learn. Further on the front-end side: React Native to build mobile apps, D3 for data visualization, other single-page MVC front-end frameworks, etc. All that stuff is best learned when you’ve got something you want to build that requires “the perfect tool for the job.” If you’re excited to expand your horizons further, you can now look at back-end technologies to start building full-stack applications. If you’re on the Ruby on Rails path, you’re already there if you’ve completed the preceding courses!
So where do you go from here? BUILD! Build and build and build and build (see a theme in this curriculum yet?). Use what you’ve learned to create great projects. But focus on creating interesting software and use that to drive your education. However, we’re not done yet. There is yet more to learn!
This section contains helpful links to other content. It isn’t required, so consider it supplemental for if you need to dive deeper into something.