How to compile the example given in the book correctly? When
compiling, an error occurs that the main function is missing. If
I replace `shared static this()` with `void main()', then
everything starts. What does the compilation string in `dub` and
`dmd` look like correctly?
```d
import vibe.d;
shared static this()
{
auto settings = new HTTPServerSettings;
settings.port = 8080;
settings.bindAddresses = ["::1", "127.0.0.1"];
listenHTTP(settings, &hello);
logInfo("Please open http://127.0.0.1:8080/ in your browser.");
}
void hello(HTTPServerRequest req, HTTPServerResponse res)
{
res.writeBody("Hello, World!");
}
```
