Listing 3.1 Gemfile

As in Section 2.1, our next step is to use a text editor to update the
Gemfile with the gems needed by our application. On the other hand, for
the sample application we’ll also need two gems we didn’t need before:
the gem for RSpec and the gem for the RSpec library specific to Rails.
The code to include them is shown in Listing 3.1. (Note: If you would
like to install all the gems needed for the sample application, you
should use the code in Listing 9.47 at this time.)