Websockets support

Added `Upgrade` and `Connection` headers to the template to allow nginx to [upgrade a request](http://nginx.com/blog/websocket-nginx/). 

```
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
```

These headers are only added if a `WEBSOCKETS` environment variable is defined.
Websockets support in README
Fixed comment syntax error
Merge pull request #1 from saidimu/patch-1

Websockets support