Game Application use-case User use-cases Register user can register to application by phone number Login user can log in to the application by phone number and password Game use-cases Each game have a given number of questions The difficulty level of questions are "easy, medium, hard" Game winner is determined by number of correct answers that each user answered Each game is belonged to specific category: sport, history, etc entity User ID Phone number Avatar Name Game ID Category Question List Players Winner Question ID Question Answer List Correct Answer Difficulty Category