How to enable verbose logging during application run

[Venkat]

Sorry posted the above message by accident.

I am running a vibed app using `dub` command. But it produces no 
logging what so ever when requests are made. The server returns 
http error codes but it doesn't log anything to the console. How 
do I make it show me a lot more detail than it is doing now ?

For example, in a Java webapp, one would change the logging level 
to debug if a logging library is configured.