Document file injection usage.

Continuation of #31 now that #47 and #56 have been merged.

The current config file situation is rather sad and I think the solution is to eliminate it entirely.

| Option | Default | Description |
|----------|-----------|-----------------|
| prepare[] command | npm rebuild; npm install --production | Prepares the application for deployment. |
| start command | slc run --cluster=cpus | Starts the application. |
| stop signal | SIGTERM Stops the application.
restart signal	SIGHUP	Restarts the application,
[files] section	N/A	Specifies files to add to the application directory. See Adding files.