code: function(url, data) {
              return $.ajax({
                  url: url,
                  data: ko.toJSON(data),
                  type: 'POST',
                  contentType: 'application/json',
                  dataType: 'json'
              });
          }
docs: Makes an HTTP POST request.
  @method post
  @param {string} url The url to send the post request to.
  @param {object} data The data to post. It will be converted to JSON. If the data contains Knockout observables, they will be converted into normal properties before serialization.
  @return {Promise} A promise of the response data.