title: knockout dynamically replace a object in an observable array
body: <p>I have knockout observable array like</p>
  
  <pre><code>var viewModel={
         people : ko.observableArray([
              { name: 'Bert' },
              { name: 'Charles' },
              { name: 'Denise' }
          ])};
   ko.applyBindings(viewModel);
  </code></pre>
  
  <p>with foreach binding i have displayed the array in a table
  now i want to chane the first row of the table dynamically
  using the array index 
  i tryed <code>(viewModel.people.name[0]("new value");</code> it doesn't work</p>
  
  <p>Any ideas?</p>