How to prepend a checkbox column in handsontable

I am working with handsontable and a jsfiddle http://ift.tt/1xzdQNe . I am trying to prepend a checkbox column before the data. In this there is the following js structure, which I assume is a multidimensional array:

columns: [
  {
    data: "car"
    //1nd column is simple text, no special options here
  },
  {
    data: "year",
    type: 'numeric'
  },
  {
    data: "available",
    type: "checkbox"
  }
]

If I understand correctly to get the checkboxes in the first column I'll need to make this array look something like:

columns: [
  {
   "checkboxes"
   type: "checkbox" 
  },
  {
   data: "car"
    //1nd column is simple text, no special options here
  },
....

How can I modify the array to look like this?