Added: example of external service response headers propagation (requested by @aledbf)

examples/customization/external-auth-headers/nginx/echosvc/Dockerfile

@@ -0,0 +1,5 @@
+FROM alpine:3.5
+MAINTAINER Roman Safronov <electroma@gmail.com>
+COPY echosvc /
+EXPOSE 8080
+ENTRYPOINT ["/echosvc"]

examples/customization/external-auth-headers/nginx/echosvc/echosvc.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "UserID: %s, UserRole: %s", r.Header.Get("UserID"), r.Header.Get("UserRole"))}
+
+// Sample  "echo" service displaying UserID and UserRole HTTP request headers
+func main() {
+	http.HandleFunc("/", handler)
+	http.ListenAndServe(":8080", nil)
+}