title: How to dynamically add a column and row to calculate total in each cell in knockout
body: <p>I have a simple sample data like this</p>
  
  <pre><code>var data = {
      "Lines": [
          {"Entries": [{"Hours": 5.5},{"Hours": 2.50},{"Hours": 3.75}]}, 
          {"Entries": [{"Hours": 5.1},{"Hours": 2.00},{"Hours": 4.75}]},
          {"Entries": [{"Hours": 1.2},{"Hours": 3.00},{"Hours": 2.12}]
      }]
  }
  </code></pre>
  
  <p>Here is my model</p>
  
  <pre><code>function ViewModel() {
      var self = this
      self.List = ko.observableArray([])
  
      self.LoadData = function () {
          var data = {
              "Lines": [
                  {"Entries": [{"Hours": 5.5},{"Hours": 2.50},{"Hours": 3.75}]}, 
                  {"Entries": [{"Hours": 5.1},{"Hours": 2.00},{"Hours": 4.75}]},
                  {"Entries": [{"Hours": 1.2},{"Hours": 3.00},{"Hours": 2.12}]
              }]
          }
          self.List(ko.mappings.fromJS(data.Lines))
      ////this makes every child observable
      }
      self.LoadData()
  }
  
  $('document').ready(function () {
      ko.applyBindings(new ViewModel())
  }) 
  </code></pre>
  
  <p>Here is my view</p>
  
  <pre><code>&lt;table id="myTable" class="tablesorter"&gt;
      &lt;thead&gt;
          &lt;tr&gt;
              &lt;th&gt;Mon  1 &lt;/th&gt;
              &lt;th&gt;Mon  2 &lt;/th&gt;
              &lt;th&gt;Mon  3 &lt;/th&gt;
          &lt;/tr&gt;
      &lt;/thead&gt;
      &lt;tbody data-bind='foreach:Lines'&gt;
          &lt;tr data-bind='foreach:$data.Entries'&gt;
              &lt;td&gt;
                  &lt;input type="text" data-bind="value:Hours"/&gt;
              &lt;/td&gt;
          &lt;/tr&gt;
      &lt;/tbody&gt;
  &lt;/table&gt;
  </code></pre>
  
  <p>Here is sample view</p>
  
  <p><img src="https://i.stack.imgur.com/0MuzP.png" alt="enter image description here"></p>
  
  <p>here is the output i want</p>
  
  <p><img src="https://i.stack.imgur.com/gISSm.png" alt="enter image description here"></p>
  
  <p>You can see i am adding a column and a row which need to add and these should be observables. how can i do it. I have no idea where to start from.</p>