title: How to get all possible values of the fields TFS API
body: <p>I'm trying to make a utility for working with TFS and I have a question:
  how to get all the possible options for the workitem field?</p>
  
  <p>For example I have a field "Assigned to". I need to get all the possible users for this field:
  <a href="https://gyazo.com/900ac1be671195550e1f8ec6bc619db3" rel="nofollow">https://gyazo.com/900ac1be671195550e1f8ec6bc619db3</a></p>
  
  <p>How can I do it?</p>