I've just released an alpha version of the mobile application I created during my free time between university courses. You can check it out here:
https://play.google.com/store/apps/details?id=com.boyan.asenov.getaway
I wouldn't say it's a stable release, but I would appreciate any feedback you have for now.
Generally, my feedback on apps is that a web version will provide better feedback than an 'app store' will. For example, there's no way to provide functional feedback on your app because it is unreleased and it is unreleased because it is buggy...but really it's more about the nature of the bugs.
A buggy web app might crash a web page...but unless you've invented an entirely new bug (a zero day! no less) it won't crash my browser. So it's pretty much ok to release something that's not entirely all there. And fixing a web app is the same as when Paul Graham built ViaWeb two decades ago...bugs can be fixed as soon as they appear and deployed to production as soon as they are fixed.
On the other hand, a buggy Android app has all sorts of nasty possibilities. Fixing the bug requires a major logistical undertaking...processes including packaging up new versions, submittal for approval, and worst trying to get users to update their phone with the new version of the app.
Don't misunderstand me, learning to write mobile apps is a viable skill and potentially interesting topic. On the other hand, the app store model impedes 'shipping' because there is so much more beside the 'business logic' to deal with. I mean, from what I see in the app description there's nothing in the 'business logic' of scheduling a trip that requires data that only a mobile device can provide (i.e. the user's immediate location).
So my advice with a premise of business rather than learning:
Avoid the alpha->beta->release candidate approach in favor of the Minimum Viable Product process. http://www.themacro.com/articles/2016/01/minimum-viable-prod...
And my encouragement: It is great that you are willing to take the risk of showing your work on the internet.
Good luck.