Not generating oauth_token
I have a strange problem, and I'm not even entirely sure it's with koa-passport, but I don't know where else to turn.

The code I'm using is pretty much exactly the code in the example, and up until recently, everything was working correctly.  I tried setting up a new machine to run my project, and I'm finding that on any new machine I try to set up, I can't get my app to send back an `oauth_token`.

I'm using the passport-twitter strategy only, and when I do a GET on http://127.0.0.1:3000/auth/twitter on one of my working computers, it responds back with:

`api.twitter.com/oauth/authenticate?oauth_token=XXX`

where `XXX` is the oauth_token.  When I do the same request on a non-working computer (same code, same everything else from what I can tell), I get:

`api.twitter.com/oauth/authenticate`

which obviously doesn't work.  I've tried everything I can think of to make this work and I'm absolutely stumped.  Any thoughts?
