react-router-dom.diff

 import React, { Component } from 'react';
+import { BrowserRouter, Link, Switch, Route } from 'react-router-dom';
+import Home from './Home';
+import Post from './Post';
 import logo from './logo.svg';
 import './App.css';
 
 class App extends Component {
   render() {
     return (
+      <BrowserRouter>
         <div className="App">
           <header className="App-header">
+            <Link to="/">
               <img src={logo} className="App-logo" alt="logo" />
+            </Link>
             <h1 className="App-title">Welcome to React</h1>
+            <Link to="/">Home</Link> <Link to="/post/">Post</Link>
           </header>
-        <p className="App-intro">
-          To get started, edit <code>src/App.js</code> and save to reload.
-        </p>
+          <Switch>
+            <Route exact path="/" component={Home} />
+            <Route path="/post/" component={Post} />
+          </Switch>
         </div>
+      </BrowserRouter>
     );
   }
 }