Parse Cloud Code - new user add to a role

role.js

Parse.Cloud.afterSave("_User", function (request, response) {
    Parse.Cloud.useMasterKey();
    var user = request.object;
    query = new Parse.Query(Parse.Role);
    // add user to the role named "General"
    query.equalTo("name", "General");
    query.first({
        success: function (object) {
            object.relation("users").add(user);
            object.save();
            response.success("The user has been authorized.");
        },
        error: function (error) {
            response.error("User authorization failed!");
        }
    });
});