Adds a valid robots.txt file
Adds a valid robots.txt file

Signed-off-by: Christopher Webber <cwebber@chef.io>

Pull request: #829
Approved by: fnichol

habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,rsertelon/habitat,nathenharvey/habitat,rsertelon/habitat,nathenharvey/habitat,habitat-sh/habitat,georgemarshall/habitat,habitat-sh/habitat,georgemarshall/habitat,habitat-sh/habitat,rsertelon/habitat,nathenharvey/habitat,georgemarshall/habitat,nathenharvey/habitat,nathenharvey/habitat,habitat-sh/habitat,georgemarshall/habitat,georgemarshall/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,nathenharvey/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat