Problems with Yahoo
I'm using Node and Express 3 and tried the following:

``` js
var Grant = require('grant-express')
  , grant = new Grant({
"server": { 
  "protocol" : "http",
  "host" : "[my host]:[my port]"
},
"yahoo": {
  "key": "[OAUTH CONSUMER KEY]",
  "secret" : "[OAUTH SECRET]",
  "callback" : "[host and path for callback]"
}
});

var app = express()
app.use(express.logger())
app.use(express.cookieParser())
app.use(express.cookieSession({secret:'very secret'}))
// mount grant
app.use(grant)
```

When I hit the [host]/connect/yahoo URL, I get the following:

``` js
{
  "error": {
    "oauth_problem": "consumer_key_unknown"
  }
}
```

When I try the same consumer key and secret on the OAuth Playground app on your Heroku instance, with the Yahoo provider, it works fine.
