even more improved multiple_upstream example (#330, #388)

etc/caddy/multiple_upstream.Caddyfile

@@ -1,10 +1,18 @@
+# Multiple Backends Example
+#
 http:// {
+    # Bind to the zrok share
 	bind {{ .ZrokBindAddress }}
+
+    # Handle paths starting with `/zrok/*`
+    # This will also strip the `/zrok/` from the path before sending to the backend
 	handle_path /zrok/* {
 	    reverse_proxy https://zrok.io {
 	        header_up Host zrok.io
 	    }
 	}
+
+	# All other traffic goes to localhost:3000
 	reverse_proxy /* 127.0.0.1:3000 {
 		header_up Host localhost:3000
 	}