title: Webpack - _ is not defined
body: <p>When I run webpack, <code>_</code> returns as undefined on window: <code>window._ ::: Error: _ is not defined</code>. I thought that putting <code>_</code> inside the plugins will expose it to <code>window</code>. Is my understanding incorrect?</p>
  
  <pre><code>const webpack = require('webpack');
  
  const plugins = new webpack.ProvidePlugin({
      $: "jquery",
      _: "underscore"
  });
  
  module.exports = {
      entry: {
          app: './src/main/app/components/main.module.js',
          vendor: [
              'jquery',
              'underscore'
          ]
      },
      output: {
          filename: './src/main/resources/dist/app/scripts/[name].bundle.js',
      },
      plugins: [plugins],
      devtool: 'inline-source-map'
  };
  </code></pre>