Kata

Your job is to add a method 'sum' to all array objects, which sums all the numbers in it. You should return 0 if the array is empty.

For example:

var arr = [1,2,3,4];
arr.sum();  //returns 10

var arr = [10, 28, 14, 33];
arr.sum(); //returns 85

arr = [1,2,3,4]
arr.sum();  #returns 10

arr = [10, 28, 14, 33]
arr.sum(); #returns 85

Good luck!