Need to fix authentication

[oconnelc]

Currently if you try and login locally, the following exception is seen:
TypeError: Cannot read property 'then' of undefined
at Strategy._verify (sentimentaltweet/index.js:27:5)
at Strategy.authenticate (sentimentaltweet/node_modules/passport-local/lib/strategy.js:88:12)
at attempt (sentimentaltweet/node_modules/passport/lib/middleware/authenticate.js:341:16)
at authenticate (sentimentaltweet/node_modules/passport/lib/middleware/authenticate.js:342:7)
at Layer.handle as handle_request
at next (sentimentaltweet/node_modules/express/lib/router/route.js:131:13)
at Route.dispatch (sentimentaltweet/node_modules/express/lib/router/route.js:112:3)
at Layer.handle as handle_request
at sentimentaltweet/node_modules/express/lib/router/index.js:277:22
at Function.process_params (sentimentaltweet/node_modules/express/lib/router/index.js:330:12)