A user on AndroidPolice pointed out that it could now be installed on Android TV through the Play Store. I installed it from the web Play Store, and it worked, but the app doesn't appear in the Leanback launcher :( you still have to launch it through settings. But it appears to have full controller support and everything worked great on my Shield.
Perhaps you guys should email Mojang and ask them to add support for the Leanback launcher!
Just spam them with tweets. I've been playing it for awhile on AndroidTV. It's not as good as keyboard and mouse but its better then touch screen.