title: How to Compute initial state of checkbox and subsribe to later state changes in knockout
body: <p>I want to check/uncheck a checkbox in the initial pageload based on a computed value. Later when the user checks/unchecks the checkbox I want to capture that.</p>
  
  <pre class="lang-html prettyprint-override"><code> &lt;div class="col-sm-9 col-md-9 pull-right"&gt;
          &lt;input type="checkbox" class="control-label" data-bind="checked:IsGroup" /&gt;
          &lt;label class="control-label form-label" style="text-align:center;vertical-align:middle"&gt;Medical Group&lt;/label&gt;
      &lt;/div&gt;
  </code></pre>
  
  <pre class="lang-javascript prettyprint-override"><code>self.IsGroup = ko.computed(function () {
          return someValue == null ? false : true;
      });
  
  self.IsGroup .subscribe(function (newValue) {
          if (newValue) {
  
              alert(newValue);
          }
          else {
              alert(newValue);
          }
      });
  </code></pre>
  
  <p>The subscribe event is not firing. How to approach this scenario?</p>