Login-Issues, session can't be saved

Nobody has claimed this yet.

There seems to be an issue with the session-handling at the moment when trying to log in:
```
TypeError: req.session.save is not a function
at Routes.authGithubCallback (/usr/src/app/lib/routes.js:15:15)
at Layer.handle [as handle_request] (/usr/src/app/node_modules/express/lib/router/layer.js:95:5)
at next (/usr/src/app/node_modules/express/lib/router/route.js:131:13)
at complete (/usr/src/app/node_modules/passport/lib/middleware/authenticate.js:250:13)
at /usr/src/app/node_modules/passport/lib/middleware/authenticate.js:257:15
at pass (/usr/src/app/node_modules/passport/lib/authenticator.js:421:14)
at Authenticator.transformAuthInfo (/usr/src/app/node_modules/passport/lib/authenticator.js:443:5)
at /usr/src/app/node_modules/passport/lib/middleware/authenticate.js:254:22
at /usr/src/app/node_modules/passport/lib/http/request.js:60:7
at pass (/usr/src/app/node_modules/passport/lib/authenticator.js:267:43)
at serialized (/usr/src/app/node_modules/passport/lib/authenticator.js:276:7)
at /usr/src/app/lib/routes.js:394:9
at model. (/usr/src/app/node_modules/mongoose/lib/document.js:1913:20)
at next_ (/usr/src/app/node_modules/mongoose/node_modules/hooks-fixed/hooks.js:89:34)
at fnWrapper (/usr/src/app/node_modules/mongoose/node_modules/hooks-fixed/hooks.js:186:18)
at /usr/src/app/node_modules/mongoose/lib/model.js:3361:16
```
With the following on reload:
```
InternalOAuthError: Failed to fetch user profile
at /usr/src/app/node_modules/passport-github2/lib/strategy.js:96:19
at passBackControl (/usr/src/app/node_modules/passport-github2/node_modules/passport-oauth2/node_modules/oauth/lib/oauth2.js:123:9)
at IncomingMessage. (/usr/src/app/node_modules/passport-github2/node_modules/passport-oauth2/node_modules/oauth/lib/oauth2.js:143:7)
at emitNone (events.js:72:20)
at IncomingMessage.emit (events.js:166:7)
at endReadableNT (_stream_readable.js:905:12)
at nextTickCallbackWith2Args (node.js:441:9)
at process._tickCallback (node.js:355:17)
```

Start at lib/routes.js:15 and reproduce the GitHub login flow that triggers the session error. Compare the initial login failure with the reload-related InternalOAuthError in the report, then verify that login completes, the session is saved, and reload no longer fails.

Written by the indexing model from the issue text.