services.js : added new function userStatusAttend() to change the participant status to attended, once the user pushed the Geo. button.
services.js : added new function userStatusAttend() to change the participant status to attended, once the user pushed the Geo. button.

clemens-huebner/amos-ss16-proj8,clemens-huebner/amos-ss16-proj8,clemens-huebner/amos-ss16-proj8