title: DynamoDB: Appending an element to a list using Node.js
body: <p>This doesn't work. Is there another way to do this? <code>cord</code> is a list to which I want to add a map.</p>
  
  <pre><code>var params5 = {
    TableName: 'rides',
    Key: {
      'rid': data2.Items[0].rid
    },
    UpdateExpression: 'add cord :x',
    ExpressionAttributeValues: {
      ':x': [{date: secondStartDate.toString(), latitude: xcorpassed, longitude: ycorpassed}]    
    },
    ReturnValues: 'UPDATED_NEW'
  }
  docClient.update(params5, function (err5, data5) { ... }
  </code></pre>