Add ION authentication library.
Merge branch 'master' of github.com:manhhung741/hotel-booking-2102

* 'master' of github.com:manhhung741/hotel-booking-2102:
  fix bug from hotel model
  update hotel model
add user authentication syste.
Merge branch 'master' of github.com:manhhung741/hotel-booking-2102

* 'master' of github.com:manhhung741/hotel-booking-2102:
  update constructor hotel model
Merge branch 'hung-dev'

* hung-dev:
  add user authentication syste.