Updated some things in the frontend

- App zeigt nun eine Zeit an, wenn backend zur verfügung steht
- Docker-Port ist auf 3000, weil Standard

frontend/docker-compose.yml

@@ -10,6 +10,6 @@ services:
       - '.:/app:z'
       - '/app/node_modules'
     ports:
-      - 3001:3000
+      - 3000:3000
     environment:
       - CHOKIDAR_USEPOLLING=true

frontend/src/App.js

@@ -1,13 +1,25 @@
-import React from 'react';
-import HelloWorld from './HelloWorld';
+import React, { useState, useEffect } from 'react';
+import logo from './logo.svg';
 import './App.css';
 
 function App() {
-  return (
-      <div classname="App">
-          <HelloWorld />
-      </div>
-  );
+      const [currentTime, setCurrentTime] = useState(0);
+
+      useEffect(() => {
+              fetch('/time').then(res => res.json()).then(data => {
+                        setCurrentTime(data.time);
+                      });
+            }, []);
+
+      return (
+              <div className="App">
+                <header className="App-header">
+
+
+                  <p>The current time is {currentTime}.</p>
+                </header>
+              </div>
+            );
 }
 
 export default App;