config/comparison_feed_hosts.yml
:froogle: 
  :filename: froogle.tsv
  :host: www.froogle.com
  :headers: !ruby/struct:Foo 
    bar: test1
    nih: test2

# in script/console
>> YAML::load(File.open("#{RAILS_ROOT}/config/comparison_feed_hosts.yml"))
TypeError: invalid subclass
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `transfer'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `node_import'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load'
        from (irb):2