CH11: Testing Controllers with Authentication

When running mocha on the updated `test/server/controllers/api/posts.spec.js` file, the test fails with the following error:
```
2 passing (287ms)
1 failing

1) controllers.api.posts
POST /api/posts
"before each" hook:
Uncaught TypeError: websockets.broadcast is not a function
at controllers/api/posts.js:41:13
at RedisClient. (pubsub.js:12:3)
at return_pub_sub (node_modules/redis/index.js:786:18)
at RedisClient.return_reply (node_modules/redis/index.js:833:9)
at JavascriptRedisParser.returnReply (node_modules/redis/index.js:192:18)
at JavascriptRedisParser.execute (node_modules/redis-parser/lib/parser.js:574:12)
at Socket. (node_modules/redis/index.js:274:27)
at readableAddChunk (_stream_readable.js:176:18)
at Socket.Readable.push (_stream_readable.js:134:10)
at TCP.onread (net.js:547:20)
```
In the `controllers/api/posts.js` file, this is where the code breaks:

```
pubsub.subscribe('new_post', function(post) {
websockets.broadcast('new_post', post)
})
```

My guess is that ```websockets``` is not available to the testing code, but i'm unsure on how to resolve this.