Fixing find by ID air

ReferenceError: findById is not defined
   at /root/expressLitter/app.js:50:3
   at pass (/root/expressLitter/node_modules/passport/lib/authenticator.js:353:9)
   at Authenticator.deserializeUser (/root/expressLitter/node_modules/passport/lib/authenticator.js:358:5)
   at SessionStrategy.authenticate (/root/expressLitter/node_modules/passport/lib/strategies/session.js:49:28)
   at attempt (/root/expressLitter/node_modules/passport/lib/middleware/authenticate.js:341:16)
   at Object.authenticate [as handle] (/root/expressLitter/node_modules/passport/lib/middleware/authenticate.js:342:7)
   at next (/root/expressLitter/node_modules/express/node_modules/connect/lib/proto.js:169:15)
   at Object.initialize [as handle] (/root/expressLitter/node_modules/passport/lib/middleware/initialize.js:62:5)
   at next (/root/expressLitter/node_modules/express/node_modules/connect/lib/proto.js:169:15)
   at multipart (/root/expressLitter/node_modules/express/node_modules/connect/lib/middleware/multipart.js:94:61)