6.3.4 User has Secure Password

In previous versions of Rails, adding a secure password was difficult
and time-consuming, as seen in the Rails 3.0 version of the Rails
Tutorial,18 which covers the creation of an authentication system from
scratch. But web developers’ understanding of how best to authenticate
users has matured enough that it now comes bundled with the latest
version of Rails. As a result, we’ll complete the implementation of
secure passwords (and get to a green test suite) using only a few lines
of code.