added initial components and routing

src/App.js

@@ -1,5 +1,15 @@
+import React from 'react';
+import { Route, Routes } from 'react-router-dom';
+import Home from './components/Home';
+import Board from './components/Board';
+import Thread from './components/Thread';
+
 function App() {
-  return null;
+  return <Routes>
+    <Route path='/' element={<Home />} />
+    <Route path='/board' element={<Board />} />
+    <Route path='/board/:thread' element={<Thread />} />
+  </Routes>
 }
 
 export default App;