This is a basic games server.

Entities:

user - 
  fb login
  identity for gameplay
  list of users

game_type
  a type of game - battleship, asteroids, doom, etc

game - a contest
  takes n users - who are then players. 
  state - waiting, in progress, finished
  list of games in progress
  list of finished games
  list of games started, waiting for players

player
  association btwn game and user
  score
  high scoring players (per game)

room - container for the game and players
  list of rooms
  rules per room, like table limits, number of players
  contains a game

lobby - 
  list games
  list players

turn - given to one of the game players