add link to docu

[rdp]

Based on the README it feels like WEBrick can only serve static files.

Suggestion/feature request: add a link to where more example can be found, ex: https://docs.ruby-lang.org/en/2.4.0/WEBrick.html
Cheers!

[jeremyevans]

Near the top of the README, it states WEBrick includes servlets for handling CGI scripts, ERB pages, Ruby blocks and directory listings.. So I'm not sure why it would give the feeling that WEBrick can only serve static files.

I'm against linking to documentation for a particular Ruby version, since that will become outdated.

That being said, if you want to send a pull request to add text/examples to the README showing more of WEBrick's capabilities, I think that would be a helpful addition.