Using Parse.com REST-API with AngularJS

Question

I would like to use Parse with AngularJS. I'm a new one in both... I'm trying to create a new user but i receive the error "bad request".

Here is my controller (linked to two input html tags):

var myAppControllers = angular.module('myApp.controllers', []);

myAppControllers.controller('SignUpCtrl', ['$scope', '$http',
  function($scope, $http) {
    $scope.results = []

        $scope.signUp = function() {
         $http({method : 'POST',
                url : 'https://api.parse.com/1/users', 
                headers: { 'X-Parse-Application-Id':'xxx', 'X-Parse-REST-API-Key':'xxx'},
                params: {
                    where: {
                        username: $scope.username,
                        password: $scope.password
                    }

                }}  )
            .success(function(data, status) {
                $scope.results = data;
             })
            .error(function(data, status) {
                alert("Error");
            })
        }
  }]);