A small code snippet that shows how to return items from a relation since include is only for pointer columns (parse.com javascript SDK)

include-relation.js

function get(req, res) {

  var Foo,
    query,
    foos;

  Foo = Parse.Object.extend("Foo", {}, {});
  query = new Parse.Query(Foo);
  foos = [];

  query.
    each(function(foo){
      var bar = foo.relation("bar");
      return bar.query().find().
            then(function(bar){
              // do stuff
              // push the foos to an array to have them acessable later
              foos.push(foo);
              // just to return something successfully. The iteration will only continue if a promise is returned successfully
              // https://parse.com/docs/js/api/classes/Parse.Query.html#methods_each
              return Parse.Promise.as(foo);
            }, cm.promiseHandleError);

    }, function(error){
      return Parse.Promise.error(error);
    }).
    then(function () {
      res.json({foos: foos});
    }, function(error){
      res.status(500).json("Error retrieving list of foos.");
    });
}