If you want an app to actually build and run the whole install on your phone using official Debian repos, check out Lil' Debi.  Its a Debian debootstrap chroot builder and manager:

https://github.com/guardianproject/lildebi

It is a completely open source app, everything used by the app is built from source that is included in the app, except for one optional util: gpgv.  That you can build yourself using https://github.com/guardianproject/gnupg-for-android