A `user` can `create` an account. * using a `google` account. * using a `facebook` account. * using a `git hub` account. * `manually create` an account. A `user` can `sign in`. A `user` can `change` the password.
A
usercancreatean account.googleaccount.facebookaccount.git hubaccount.manually createan account.A
usercansign in.A
usercanchangethe password.