You know what always comes after pigging out during the holidays: a New Year's resolution to get fit, this time (you swear!) for sure. Well, Nike's hoping to kickstart your quest to fitness by updating its Nike Training Club (N+TC) apps for Android and iOS. New features include the ability to customize exercise routines, as well as earn reward content and sharable milestones whenever you reach a goal. Nike has also added six new exercise videos (of athletes and celeb trainers) to its archive of more than a hundred. Other than that, the app's now more tightly integrated with other Nike products: it's now possible to add minutes from each run on the separate Running app to your N+TC total, and you can tag N+TC sessions on the FuelBand app. The update will hit both platforms' app stores on December 31st -- just in time to make you feel less guilty about that third slice of cheesecake on New Year's Eve.