title: What Rest API definition to use when moving items between collections
body: <p>I am building a REST/JSON based service which has in it's API a couple of collections that contain items. All these items are of the same type.</p>
  
  <p>As an example: The service much resembles a TODO list with collections for items that still need to be done, are in the progress of being completed and are finished.</p>
  
  <p>The API would be something like</p>
  
  <pre><code>/todo/new
  /todo/inprogress
  /todo/finished
  </code></pre>
  
  <p>So how would one define an instruction to move an item from the /todo/new to the /todo/inprogress ?</p>
  
  <p>Basically both collections are as much responsible to perform the move. Should one of them be responsible? or should I make another API called /todo/item which will receive the move instruction?</p>