title: How do I create new field of 'string' type?
body: <p>My intention is to create a new field. Actually I need few fields:</p>
  
  <ol>
  <li>"AdditionalAnswer required" with values "yes" and "no";</li>
  <li>"Custom Level" with any text value from the list "1-cool", "2-middle", "3-low".</li>
  </ol>
  
  <p>Type for both of them should be 'string'. I've exported work item type, and added the new field.  Now the problem is that I don't see the most appropriate value type to be specified as the "RefName" for string type. For "Priority" field (that is really a string) special "System.Priority" RefName is used.</p>
  
  <p>How can I create own value? This value should be filtered with "queries".</p>
  
  <p>Any thoughts are welcome.</p>
  
  <p>Thanks!</p>