upstream module

[oscarmartins]

Everything is working as expected, thank you.
Now I would like to know how I could add the upstream module?
Like:
upstream backend {
server backend1.example.com weight=5;
server backend2.example.com:8080;
server unix:/tmp/backend3;

server backup1.example.com:8080   backup;
server backup2.example.com:8080   backup;

}