@klevismiho I have the exact same problem, OSX Yosemite, inserted tasks following tutorial, and confirmed that collection was created. But nothing shows on frontend.
@vadik what you said makes sense, but according to the tutorial, we wouldn't need to. Here's a quote of the tutorial right after the step of inserting tasks:
"In your web browser, you will see the UI of your app immediately update to show the new task. You can see that we didn't have to write any code to connect the server-side database to our front-end code — it just happened automatically."