Setting up Action Mailer

I'm trying out Action Mailer for the first time. I'm not getting to
first base. I thought that the instructions were pretty clear in that
the first thing that I needed to do is to add:

config.action_mailer.delivery_method = :smtp | :sendmail | :test

to config/environment.rb (assuming that I want to use the same
configuration for development, testing, and production).

So, I added:

config.action_mailer.delivery_method = :sendmail

to the end of config/environment.rb right below where it says:

# Include your application configuration below

Now when I try to start the web server I get:

/home/doug/test1/config/environment.rb:62: undefined local variable or
method `config' for main:Object (NameError)

Any suggestions on what I might be doing wrong? Thanks for any input.

      ... doug