title: Webpack not working when React is introduced
body: <p>I have followed the main tutorial on webpack and I have got the server up and running. When I change files, it will update on save, all is good.
  However, I then introduced React and it all went wrong.</p>
  
  <p>Firstly, I am getting this error in the browser: </p>
  
  <pre><code>Unexpected token &lt;
  You may need an appropriate loader to handle this file type.
  </code></pre>
  
  <p>This is pointing to line 4 in my entry.js file:</p>
  
  <pre><code>var CommentBox = React.createClass({
    render: function() {
      return (
          &lt;div className="commentBox"&gt;
            Hello, world! I am a CommentBox.
          &lt;/div&gt;
      );
    }
  });
  ReactDOM.render(
      &lt;CommentBox /&gt;,
      document.getElementById('content')
  );
  </code></pre>
  
  <p>This is index.html</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
      &lt;meta charset="utf-8"&gt;
  &lt;/head&gt;
  &lt;body&gt;
  
      &lt;div id ="content"&gt;&lt;/div&gt;
  &lt;script type="text/javascript" src="bundle.js" charset="utf-8"&gt;&lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>webpack.config.js:</p>
  
  <pre><code>module.exports = {
    entry: "./entry.js",
    output: {
      path: __dirname,
      filename: "bundle.js"
    },
    module: {
      loaders: [
        {
          test: /\.jsx?$/,
          loader: 'jsx-loader?insertPragma=React.DOM&amp;harmony'
        }
      ]
    },
    externals: {
      'react': 'React'
    },
    resolve: {
      extensions: ['', '.js', '.jsx']
    }
  };
  </code></pre>
  
  <p>If I change the <code>entry.js</code> file to just contain:</p>
  
  <pre><code>document.write(require("./content.js"));
  </code></pre>
  
  <p>It produces what I currently have in the content.js file:</p>
  
  <pre><code>module.exports = "this is working";
  </code></pre>
  
  <p>So therefore it is something to do with react/jsx etc. Anyone got any solutions to this? I have seen other people online with this issue but the solutions given have not worked for me so far.</p>