example can not build

[TimChenTranzas]

I try the helloworld example, but it fails with the dudac client

--
root@vultr:~/duda-examples/001_hello_world# make
[CC] main.o
main.c: In function ‘_duda_main’:
main.c:95:5: error: ‘router’ undeclared (first use in this function)
router->map("/foo/", cb_foo);
^
main.c:95:5: note: each undeclared identifier is reported only once for each function it appears in
Makefile:25: recipe for target 'main.o' failed
make: *** [main.o] Error 1