title: Webpack: can't find bundle.js
body: <p>I've finally got the he dev server running and I get something on screen.
  I've setup a "start" script for NPM like this:</p>
  
  <pre><code>"start": "webpack-dev-server --content-base app"
  </code></pre>
  
  <p>I get an error: </p>
  
  <pre><code>http://localhost:8080/bundle.js Failed to load resource: the server responded with a status of 404 (Not Found)
  </code></pre>
  
  <p>My folders are set as follows:</p>
  
  <pre><code>appDir
    -&gt;app
    -&gt;node_modules
    webpack.config.js
    package.json
  </code></pre>
  
  <p>My webpack.config.js:</p>
  
  <pre><code>module.exports = {
      context: __dirname + '/app',
      entry: './index.js',
      output: {
          path: __dirname + '/app',
          filename: './bundle.js'
      }
  }
  </code></pre>
  
  <p>Can you tell what's wrong?</p>