Simplify computations of user data regarding username, user id
  - [X] Install board setup routine (C-c o I) also install board users
  - [X] Create board routine (C-c o i) should also install user boards (only the current user should then appear)
  - [X] Setuping properties before doing any actions
  - [X] Cleanup routine should also remove user properties
  - [X] User assigns oneself to the card