configuring the root url for a Heroku Grails app
===

I'm using the Grails stack on Heroku to deploy an app.  I'd like to be able to serve my app with a root of `myapp.herokuapp.com/xyz` as opposed to `myapp.herokuapp.com`, in the same way I'm able to serve from root of `localhost:8080/xyz` in development. I've tried adding a `grails.app.context` in Config.groovy like so:

    environments {
        production {
    	    	grails.app.context = "/xyz"
        }
    }

But it doesn't seem to have an effect in deployment. Do I have to configure something with Heroku? Any ideas?