change to right listen port. (#86)

diff --git a/examples/nginx.conf b/examples/nginx.conf
index 145bebd..c37bf23 100644
--- a/examples/nginx.conf
+++ b/examples/nginx.conf
@@ -74,7 +74,7 @@
                 -- skywalking_tracer:start("upstream service", {custom = "custom_value"})
             }
 
-            proxy_pass http://127.0.0.1:8080/tier2/lb;
+            proxy_pass http://127.0.0.1:8090/tier2/lb;
 
             body_filter_by_lua_block {
                 if ngx.arg[2] then
@@ -94,7 +94,7 @@
                 skywalking_tracer:start("backend service")
             }
 
-            proxy_pass http://127.0.0.1:8080/backend;
+            proxy_pass http://127.0.0.1:8090/backend;
 
             body_filter_by_lua_block {
                 if ngx.arg[2] then