title: GraphQL object property should be a list of strings
body: <p>How do I make a schema for an object property that is an array of strings in GraphQL?  I want the response to look like this:</p>
  
  <pre><code>{
    name: "colors",
    keys: ["red", "blue"]
  }
  </code></pre>
  
  <p>Here is my Schema</p>
  
  <pre><code>var keysType = new graphql.GraphQLObjectType({
    name: 'keys',
    fields: function() {
      key: { type: graphql.GraphQLString }
    }
  });
  
  var ColorType = new graphql.GraphQLObjectType({
    name: 'colors',
    fields: function() {
      return {
        name: { type: graphql.GraphQLString },
        keys: { type: new graphql.GraphQLList(keysType)
      };
    }
  });
  </code></pre>
  
  <p>When I run this query I get an error and no data, the error is just <code>[{}]</code> </p>
  
  <p><em>query { colors { name, keys } }</em></p>
  
  <p>However when I run a query to return just the name I get a successful response. </p>
  
  <p><em>query { colors { name } }</em></p>
  
  <p>How do I create a schema that returns an array of strings for when I query for keys?</p>