If you go to your account--- setup--- analytics--- you should be able to put them in the javascript section. However, we do have full-fledged analytics under the Insights tab of your LaunchRock campaign, so you do not need Google Analytics.
If you would still like to connect your LaunchRock to Google Analytics, you will need to custom inject the tracking code into your project. We do not provide support for this custom code, but you can get more support at Google Analytics Support.