title: Group By id and Sum get sum to set new using Lodash
body: <p>Would it be possible to sort and group by (say, "id") and update the values of the Elements by adding all unique values of the Key (eg: payout) using Lodash?<br />
  For example, could this array below:</p>
  
  <pre><code>[
    {
       id: 1,
       payout: 15,
       numOfPeople: 4
    },
    {
       id: 1,
       payout: 12,
       numOfPeople: 3
    },
    {
       id: 2,
       payout: 6,
       numOfPeople: 5
    },
    {
       id: 2,
       payout: 10,
       numOfPeople: 1
    }
  ]
  </code></pre>
  
  <p>... be transformed into the one like below using LODASH:<br /></p>
  
  <pre><code>  // Notice the Sum of all payout reflects the total sum of all
    // payout with id=1 or id=2 (for a specific id Group)
  
  [
    {
       id: 1,
       payout: 27,
       numOfPeople: 4
    },
    {
       id: 1,
       payout: 27,
       numOfPeople: 3
    },
    {
       id: 2,
       payout: 16,
       numOfPeople: 5
    },
    {
       id: 2,
       payout: 16,
       numOfPeople: 1
     }
   ]
  </code></pre>