title: How to force all nodes in yaml to be strings
body: <p>I have a huge config yaml file, where all of the nodes should be read as strings. An example:</p>
  
  <pre><code>model_names:
    Audi:
      A4:
        - A4
        - A 4
    Fiat:
      500:
        - 500  
  </code></pre>
  
  <p>I load out the file in rails:</p>
  
  <pre><code>catalogue = File.read("#{Rails.root}/config/cars_catalogue.yml")
  CARS_CATALOGUE = YAML.load(catalogue)
  </code></pre>
  
  <p>My problem is, that if I ask for:</p>
  
  <pre><code>CARS_CATALOGUE['model_names']['Fiat']['500']
  </code></pre>
  
  <p>It returns nil, because it thinks that 500: is a fixnum - but all of the nodes should ALWAYS be strings - and i don't want to enforce this with quotes everywhere in the yaml file. So how do I do this in a simple and smart way? </p>