Me and 3 others recently built an Android app as part of an Android Development class at UVM. It has a companion website, and uses it for its database.
The app was written in Java using Android Studio and all it's accompanying tools. The website was written on WordPress. We developed on the WordPress Rest API to do all out communication between the app, and the database. The main idea is this: At computer science fairs (and any other competitions), there are things need to be judged. In this case, CS projects. The system allows an admin to assign judges to judging groups, and projects to judging groups. All of this is encapsulated in event years, so it can be repeated and archived year after year. The judging groups can have completely custom criteria, and can be changed any time. Turned out pretty neat. At the end we added a QR code scanner so that at the CS fair each project can have a QR code that judges can quickly scan to pull up the information for judging.
Here is what it turned out like. We also added somes flags and image assets to our website so that Android phones and iPhones will treat it extra special (more like an app) if you add the website to your home screen. Gives you the appropriate icon and pulls it out separately from other safari tasks in the task switcher.
The tough part about this project was that not a single one of us had ever used an Android phone... so we didn't really know what the conventions where, how the back button was typically used, and what the page transitions meant and looked like in certain situations.