it is something

src/server/server.go

@@ -18,7 +18,7 @@ func (s Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			log.Println("[ws]", err)
 		}
 	default:
-		http.FileServer(http.Dir("./public")).ServeHTTP(w, r)
+		http.FileServer(http.Dir("./src/public")).ServeHTTP(w, r)
 	}
 }