How can I use Docker Hub in Terraform? The instructions in Terraform Docker Provider give the example:

# Configure the Docker provider
provider "docker" {
  host = "tcp://127.0.0.1:2376/"
}

# Create a container
resource "docker_container" "foo" {
  image = "${docker_image.ubuntu.latest}"
  name  = "foo"
}

resource "docker_image" "ubuntu" {
  name = "ubuntu:latest"
}


I'm assuming this is pointing to an on-prem docker source. How do I used Docker Hub directly?
This can be done with docker_registry_image:

data "docker_registry_image" "ubuntu" {
  name = "ubuntu:latest"
}

resource "docker_image" "ubuntu" {
  name          = "${data.docker_registry_image.ubuntu.name}"
  pull_triggers = ["${data.docker_registry_image.ubuntu.sha256_digest}"]
}