Goal - social-productivity web app

I'm a musician, and sometimes it's hard to practice consistently with method. Once, a friend (and musician too) told me a trick: At the end of the day, write someone what and how much you have practiced. I tried it, and it worked incredibly well. So I decided to create an app, where you can track your activities and share with other people. This can be applied to any type of goal, sport, study, work!