deleted go.mod, not able to use go 1.13

go.mod

-module git.gvk.idi.ntnu.no/johannta/Client
-
-go 1.12

main.go

+package main
+
+import (
+	"fmt"
+	"html"
+	"log"
+	"net/http"
+	"os"
+)
+
+//Server that prints halli
+
+func helloHandler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
+}
+
+func main() {
+	port := os.Getenv("PORT")
+	port = "8080"
+
+	if port == "" {
+		log.Fatal("$PORT must be set")
+	}
+
+	http.HandleFunc("/", helloHandler)
+
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}

main_test.go

+package main
+
+func main() {
+	$END$
+}