title: Parse.com CloudCode add user to existing role not working
body: <p>Here is the Parse javascript cloud code I am trying to use. As a new _User is created I want to add them to my 'Client' Role. </p>
  
  <pre><code>Parse.Cloud.afterSave(Parse.User, function(request) {
      Parse.Cloud.useMasterKey();
  
      query = new Parse.Query(Parse.Role);
      query.equalTo("name", "Client");
      query.first ({
          success: function(role) {
              role.getUsers().add(request.user);
              role.save();
          },
          error: function(error) {
              throw "Got an error " + error.code + " : " + error.message;
          }
      });
  });
  </code></pre>
  
  <p>This is taking code directly from Parse.com's Role example. The code runs happily when a new _User is saved, returning <code>Result: Success</code>, but when I check the "users" tied to that Role in the Data Browser, nothing has happened. </p>
  
  <p>I have also tried substituting <code>role.getUsers().add(request.user);</code> for <code>role.relation("users").add(request.user);</code> as per an example on Parse.com's old forum, but no difference. This seems like it should be really straight forward, so I'm not sure what I'm doing wrong. </p>
  
  <p>(I have manually used the REST API, using curl, to add _Users to the Client Role, and this does work, so I know it should work.) </p>