title: undefined method `action_mailer' with Ruby 1.9.2 and Rails 3.0.8
body: <p>The full error is: </p>
  
  <pre><code>/Users/me/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.8/lib/rails/railtie/configuration.rb:77:in `method_missing': undefined method `action_mailer' for #&lt;Rails::Application::Configuration:0x00000102f545f8&gt; (NoMethodError)
  </code></pre>
  
  <p>I've searched several variations of this error and come up empty.</p>
  
  <p>Thanks.</p>