class MessageBird::List

def [](index) 

def [](index)
  @items[index]
end

def initialize(type, json)

List.new(Contact, {}).
type will be used to create objects for the items, e.g. 
def initialize(type, json)
  @type = type
  super(json)
end

def items=(value) 

def items=(value)
  @items = value.map { |i| @type.new i }
end