Session.addToList
Session.addToList($key, $value) -> list
Description
Append the $value to a list at the given $key.
If the $key is not yet initialized, it will first be set to an empty list [].
Returns the current list with the added item.
Session.addToList('shoppingCartItems', 'Blue Hat')
Session.addToList('shoppingCartItems', 'Green Shirt')
// ... in a later request ...
Session.get('shoppingCartItems')
//= [ 'Blue Hat', 'Green Shirt' ]