There isn't an app that will allow you to root the phone - the phone would have to be rooted in order to allow such an app to do what was necessary - Catch 22.
You'll need access to a Windows-based computer (the easiest solution - there are tools for MAC and Linux, but not as prevalent).
Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM 10.2 using Tapatalk 4