Start Iron server with handler stubs
Start Iron server with handler stubs

This commit provides the framework for handling HTTP requests. Except
for /ping, none of the handlers are implemented. Try it!

```sh
cargo build
target/debug/racerd serve --secret-file=hi --port 3000
```

In another terminal,

```sh
curl localhost:3000/ping
```

and a pong should be returned.

henriiik/racerd,jwilm/racerd,henriiik/racerd,henriiik/racerd,jwilm/racerd,jwilm/racerd