Implement resource type AWS::EC2::InternetGateway

AWS::EC2::InternetGateway
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ec2-internet-gateway.html
Creates a new Internet gateway in your AWS account. After creating the Internet gateway, you then attach it to a VPC.
The VPC creation wizard in the AWS Management Console automatically adds an Internet gateway to your VPC (depending on which scenario you select). However, you might have an existing VPC with only a virtual private gateway, and you might want to add an Internet gateway.
When you add an Internet gateway to your VPC, your goal is to have a subnet that contains public instances (instances with public IP addresses, such as web servers or a NAT instance).

Parameters
Tags

Maps to a Quantum Router gateway
quantum router-create --tenant_id [DEMO_TENANT_ID] router[x]
quantum router-gateway-set [ROUTER_ID] [EXTERNAL_NETWORK_ID]
# for each subnet in the network
quantum router-interface-add [ROUTER_ID] [SUBNET_ID]

Comments
Heat will have to be configured for policy to know what EXTERNAL_NETWORK_ID to use. An InternetGateway is assigned to a VPC, so every Quantum subnet in a net must be assigned to the router that has the gateway set on it.