Congrats!

This app has tons of PR potential, but you have to do the work. The lifehacker piece is a nice bit of social proof that you can use when contacting folks. I'd email a few dozen productivity blogs/bloggers with the new years resolution angle ("How to give your new years resolution some teeth!").

Building an app is step one. Step 2-10 is figuring out how to acquire users. Try spending literally 40 hours a week trying things on this front. Facebook ads? 2 sided referral program? Linkbait on your blog? PR hustle? Find lifehacker-y folks on Twitter and give them discount codes for their followers? Viral loops (could you get users Facebook friends to sign up?)?

Don't touch the code for 1-2 weeks and see what you can pull off! :-)