Create migration to update message urls
user
```coffeescript
Meteor.startup ->
	Migrations.add
		version: 7
		up: ->

			console.log 'Populate urls in messages'
			query = ChatMessage.find({ 'urls.0': { $exists: true }, urls: { $type: 2 } })
			count = query.count()
			query.forEach (message, index) ->
				console.log "#{index + 1} / #{count}"

				message.urls = message.urls.map (url) ->
					if _.isString url
						return {url: url}
					return url

				OEmbed.RocketUrlParser message

			console.log 'End'
```
assistant