Posting comment when logged out creates error

[markbao]

Should prevent logged-out users from accessing comment form (or posting comments).

TypeError: Cannot read property 'id' of undefined
    at exports.postComment (/app/controllers/news.js:108:21)
    at callbacks (/app/node_modules/express/lib/router/index.js:164:37)
    at param (/app/node_modules/express/lib/router/index.js:138:11)
    at param (/app/node_modules/express/lib/router/index.js:135:11)
    at pass (/app/node_modules/express/lib/router/index.js:145:5)
    at Router._dispatch (/app/node_modules/express/lib/router/index.js:173:5)
    at Object.router (/app/node_modules/express/lib/router/index.js:33:10)
    at next (/app/node_modules/express/node_modules/connect/lib/proto.js:193:15)
    at Object.handle (/app/node_modules/less-middleware/lib/middleware.js:201:91)
    at next (/app/node_modules/express/node_modules/connect/lib/proto.js:193:15)

[markbao]

Related to #105.

[megamattron]

Oops, I missed this somehow. I'll close mine.