Add order total calculation and update template display

internal/server/http.go

@@ -0,0 +1,9 @@
+package server
+
+import "net/http"
+
+func (s *Server) redirect(path string, code int) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, path, code)
+	}
+}