Added Go Code Sample to MongoHQ Language Center

Adding a code sample to a support site is not typically "blog-worthy"; however, we are ecstatic about Go. We have used Go internally for a while and find the language supports MongoHQ operational needs quite well. The mgo driver is the Go-MongoDB driver. mgo is among the best performing. As well, the driver maintains high-availability connections to MongoDB replica sets better than most drivers of other languages. To get started with a code sample, check out: http://support.mongohq.com/languages/golang.html