title: webpack config error of cannot resolve module
body: <p>When I run webpack --watch I got error of <code>Cannot resolve module 'js/app.js'</code>. And then my app.min.js did not complied when I do <code>npm run dev</code>.</p>
  
  <p>I've created a <a href="https://github.com/eldyvoon/react-webpack-babel-starter-" rel="nofollow">git repo</a> and this is my webpack.config.js</p>
  
  <pre><code>var debug = process.env.NODE_ENV !== "production";
  var webpack = require('webpack');
  var path = require('path');
  
  module.exports = {
    context: path.join(__dirname, "src"),
    devtool: debug ? "inline-sourcemap" : null,
    entry: "js/app.js", //what's wrong with this line?
    module: {
      loaders: [
        {
          test: /\.jsx?$/,
          exclude: /(node_modules|bower_components)/,
          loader: 'babel-loader',
          query: {
            presets: ['react', 'es2015', 'stage-0']        }
        }
      ]
    },
    output: {
      path: __dirname + "src",
      filename: "app.min.js" //this is not even complied?
    },
    plugins: debug ? [] : [
      new webpack.optimize.DedupePlugin(),
      new webpack.optimize.OccurenceOrderPlugin(),
      new webpack.optimize.UglifyJsPlugin({ mangle: false, sourcemap: false }),
    ],
  };
  </code></pre>