Attempting to use ajax return object to modify current object

Thing.user.js

Thing.user = new Object;
Thing.user.new = function(user){this.user = user; return this};
Thing.user._fetch_user_data = function(){
  $.ajax({ url: '/api/' + this.user
         , dataType: 'json'
         , async:false
         , success: function(data){ console.info(data); for(key in data) this.$key = data[key]; }
         });
};