So, you finished the TryRuby lessons. Are you hungry for more ?
Try to make a couple of simple programs:
You can find websites with lots more ideas (and suggested solutions) for coding problems.
Maybe you can read a book on Ruby. I’m not giving any suggestions since I want to remain impartial.
Follow an online course, of which there are many. And many are also free.
Regardless what you do, you will find the Ruby documentation an invaluable resource.
The example app BlurbalizerTM only showed the bare bones of setting up an application. Moreover it combined storing- and displaying of content. In practice these tasks are split up between a back-end application (Rails would be an excellent choice for this) and a front-end (usually a web browser or an app on your smartphone).
So if you want to create the next killer app, be sure to read all information on this website
There are a couple of articles on this website on specific topics like:
Which topics were left out of the course to keep it compact and simple.
I should mention Ruby on Rails. You have been learning the Ruby language, how to speak it. But Rails is a very powerful and popular toolkit for building websites. See the Web development article.
Today, you can use Ruby everywhere, on the Desktop, web browser, smartphone or in the cloud. See the Is there an App for that article.