service:"'my-service',optional,replicas=3,labels={'env':'prod','tier':'backend'},ports=[80,443]"

type ServiceTag struct {
	Name     string            `option:"value"`
	Optional bool              `option:"optional"`
	Replicas int               `option:"replicas"`
	Labels   map[string]string `option:"labels"`
	Ports    []int             `option:"ports"`
}

func (t ServiceTag) Tag() string {
	return "service"
}