title: Module not found: Error: Cannot resolve module 'components/app'. webpack + reactjs issue
body: <p>I'm newbie in webpack and react. hope you can help me.</p>
  
  <p>I faced a problem and can't find any working solution in the internet.
  When i trying to run webpack-dev-serverI geting "Module not found: Error: Cannot resolve module 'components/app'" error all the time.</p>
  
  <p>Here my files structure.</p>
  
  <p>root/ webpack.config.js</p>
  
  <pre><code>var webpack = require('webpack');
  var path = require('path');
  
  module.exports = {
      devtool: 'inline-source-map',
      entry: [
          'webpack-dev-server/client?http://127.0.0.1:8080/',
          'webpack/hot/only-dev-server',
          './src'
      ],
      output: {
          path: path.join(__dirname, 'public'),
          filename: 'bundle.js'
      },
      resolve: {
          moduleDirectories: ['node_modules', 'src'],
          extensions: ['', '.js']
      },
      module: {
          loaders: [{
              test: /\.js$/,
              loader: 'babel-loader',
              exclude: /node_modules/,
           query: {
               presets: ['es2015', 'react']
           }
          }]
      },
      plugins: [
          new webpack.HotModuleReplacementPlugin(),
          new webpack.NoErrorsPlugin()
      ]
  };
  </code></pre>
  
  <p>root/ .babelrc</p>
  
  <pre><code>{
      presets: ["react", "es2015"],
      plugins: ["react-hot-loader/babel"]
  }
  </code></pre>
  
  <p>root/src/index.js</p>
  
  <pre><code>import React from 'react';
  import { render } from 'react-dom';
  import App from 'components/app';
  
  render(&lt;App /&gt;, document.getElementById('app'));
  </code></pre>
  
  <p>root/src/components/app.js</p>
  
  <pre><code>import React from 'react';
  
  export default class App extends React.component {
      render() {
          return (
              &lt;div&gt;
                  &lt;h1&gt;Hello There&lt;/h1&gt;
              &lt;/div&gt;
          );
      }
  }
  </code></pre>