add l3

ci/app/main.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+    "net/http"
+    "os"
+    "fmt"
+)
+
+func indexHandler(w http.ResponseWriter, r *http.Request) {
+    w.Write([]byte("<h1>Hello World!</h1>"))
+}
+
+func main() {
+    port := os.Getenv("PORT")
+    if port == "" {
+        port = "3000"
+    }
+
+    fmt.Print("\nim run in http://127.0.0.1:", port)
+
+    mux := http.NewServeMux()
+    mux.HandleFunc("/", indexHandler)
+    http.ListenAndServe(":"+port, mux)
+}