CrewBuddy is technically an iPhone app, however it will work just fine on the iPad.  Apple changed how the App Store works on the iPad and it doesn't search for iPhone apps by default.  So, when searching the App Store, you just have to tap the little button of the top left to say iPhone Only instead of iPad Only. 

The easiest way is by tapping this link on your iPad, it will bring it up directly.  

However, here's how to find it in the App Store. 

You should see it there. It’s the one with a paper airplane.