Step 3 -> 4

3.diff

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

 $(document).ready(function() {
+    var statuses = new Statuses();
+
     $('#new-status form').submit(function(e) {
         e.preventDefault();

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