title: Problems with checklist with KnockoutJS + CoffeeScript
body: <p>I'm trying to create a simple checklist with KnockoutJS and CoffeScritp;</p>
  
  <p>For this I created a class in coffescript to represent the task.
  In this class I have a computed property <code>HasFinalized</code> to represent the check.
  Basically, if the completion date is met, then the task is completed.</p>
  
  <p>But any change in a task, it is propagated to another.</p>
  
  <p>I created an example in Findlee:  <a href="http://jsfiddle.net/Ridermansb/pr3Ah/" rel="nofollow">http://jsfiddle.net/Ridermansb/pr3Ah/</a></p>