provider "aws" {
    access_key = "a"
    secret_key = "b"
    region = "us-east-1"
}

resource "aws_instance" "foo" {
    ami = "ami-foo"
    instance_type = "t2.micro"
    security_groups = "${aws_security_group.foo.name}"
}

resource "aws_security_group" "foo" {
    name = "foobar"
    description = "foobar"
}