title: How to use or resolve enum types with graphql-tools?
body: <p>I cannot find anywhere in the <code>graphql-tools</code> documentation how one should go about utilizing <code>enum</code> types in schemas that are fed to <code>makeExecutableSchema</code>. Anyone have a clue how this done?</p>
  
  <p>Example code:</p>
  
  <pre><code>enum Color {
    RED
    GREEN
    BLUE
  }
  
  type Car {
    color: Color!
  }
  </code></pre>
  
  <p>What would the resolver for <code>Color</code> look like?</p>