I want to develop a two-player android game (turn based) called tic-tac-toe. Players will use their mobile as interface and a dedicated server will coordinate the game. I want server to run nosql, preferably, couchbase. Players total score and username should be saved in the mobile. Players should be able to play with random players or with friends from their contact list. Application will show which of their friends have installed the game. Concurrency and scalability has to be kept in mind while developing.