How can i get values of parameters using postman?

I am working on Node JS and PostgreSQL and I am creating REST web service using this. I have created a post method and calling web service through POSTMAN but unable to get parameter values in my function. Web service inserting null value in my PostgreSQL table. I am using Visual studio 2015 unable to debug code. How can I achieve this ?

queries.js

function addTask(req, res, next) {
    debugger;
    var task_name = req.body.task_name;
    var task_type = req.body.task_type;
    db.func('inserttask', [task_name, task_type])
        .then(function () {
            res.status(200)
                .json({
                    status: 'success',
                    message: 'Inserted one task'
                });
        })
        .catch(function (err) {
            return next(err);
        });
}

index.js

router.post('/api/addtask', db.addTask);

via Moin Khan