Update h2o.conf to use mruby handler

Replaced file directory configuration with mruby handler.

Author: MDA2AV

src/Servers/H2OServer/h2o.conf

@@ -1,6 +1,10 @@
 listen: 8080
+
 hosts:
   default:
     paths:
       /:
-        file.dir: /var/www
+        mruby.handler: |
+          Proc.new do |env|
+            [200, { "content-type" => "text/plain" }, ["OK"]]
+          end