don't work with router.route(path)

Hy, if you use this option of Express : router.route(path)

http://expressjs.com/fr/api.html

this package can't work : 

TypeError: app.route(...).get(...).docs is not a function

After a quick look it's normal, no time to make a PR for the moment but i will have a look on this for a solution if i can quickly :) 

Thx for your work ! 