You might want to double-check your spell lists in the current version of the app.  Hellish Rebuke (1st level evocation) is incorrectly included on the Paladin spell list as well as the Warlock.  This could lead to confusion for players who use the app rather than the official books.  As far as I can tell, that's the only spell with a problem right now.

Great app, by the way, and keep up the good work!