Build ma an android app

Hello everybody, I would like to create an app. I have following idea: There is an app called "TrainYourTeam", where a coach can send tasks (to walk a course) in a certain time. The player have to walk these courses. They have to begin the course and the coach is able to see the result at the end of the walk. My idea is: "Drunk your friend" So you can send tasks to your friends, and they have to drink (for example) 4 beers in the next 7 days. You can choose different drinks and different quantities and afterwards you can send the task to a friend, to a few friends or to a group. All members of the group (or the single friend) have to execute these tasks. As a proof of the completed task, you have to take a photo of the glass or of the bottle which you have drunk. The one who created the task have to accept the photo and the completion of the task. First of all it should be combined with Facebook (so that you can send invititations to all your facebook friends) language: english Can anybody help me? If you have any questions, please let me know.