send message to array of registrationToken

there should be some way to send a notification to array of registrationTokens ,
```js
const registrationToken = 'some user token'
const message = {
	token:registrationToken,
	data: {
		test: 'test'
	},
	notification: {
		title: "test",
		body: "test"
	},
	topic:'test'
}
```