Add migration to set channel 'GENERAL' with default: true
user
```coffeescript
Meteor.startup ->
	Migrations.add
		version: 11
		up: ->
			###
			# Set GENERAL room to be default
			###

			ChatRoom.update({_id: 'GENERAL'}, {$set: {default: true}})
			console.log "Set GENERAL room to be default"```
assistant