MAIN:

- Book court C of sport S at club X at time T for users U1,U2

* X.has_ongoing_bookings(U1)
* X.book(C, S, T, U1)

- Cancel booking B at club X for user U1

* X.cancel(B, U1)

- Get tournaments of sport S at club X

* X.get_tournaments(S)

Club:

- Book court C of sport S at time T for users U1,U2

* new ClubUserSession

- Cancel booking B for user U1
- Has user U1 ongoing booking

ClubConnector:

- land
- login user U
- book court C of sport S at time T
- has ongoing bookings
- cancel booking B
- get tournaments

UserSession

+ user
+ session
+ connector

- book

* connector.land
* connector.login
* connector.land