var postData = { userName: $scope.registrationData.userName,
                    email:    $scope.registrationData.email,
                    password: forge_sha256($scope.registrationData.password)
                  };

   var url = HOST + 'api/register.php';

   $http.post(url, postData)

$postData = file_get_contents("php://input");
   $request = json_decode($postData, true);