Step 6 -> 7

6.diff

 var Statuses = function() {
 };
 Statuses.prototype.add = function(options) {
     $.ajax({
         url: '/status',
         type: 'POST',
         dataType: 'json',
         data: { text: options.text },
         success: options.success
     });
 };

 var NewStatusView = function(options) {
     this.statuses = options.statuses;

-    $('#new-status form').submit(this.addStatus);
+    var add = $.proxy(this.addStatus, this);
+    $('#new-status form').submit(add);
 };
 NewStatusView.prototype.addStatus = function(e) {
     e.preventDefault();

     this.statuses.add({
         text: $('#new-status textarea').val(),
         success: function(data) {
             $('#statuses ul').append('<li>' + data.text + '</li>');
             $('#new-status textarea').val('');
         }
     });
 };

 $(document).ready(function() {
     var statuses = new Statuses();
     new NewStatusView({ statuses: statuses });
 });