title: Error: Cannot find module 'extract-text-webpack-plugin'
body: <p>I've installed extract-text-webpack-plugin using this command in terminal <code>sudo npm install -g extract-text-webpack-plugin</code> and imported in webpack.config.js file, still i'm getting the error.</p>
  
  <p>I also referred this question but didn't found any solution so i've posted new question.</p>
  
  <p><a href="https://stackoverflow.com/questions/33998894/webpack-extract-text-webpack-plugin-cannot-find-module">Webpack - extract-text-webpack-plugin Cannot find module</a></p>
  
  <p>Webpack.config.js file source code:</p>
  
  <pre><code>/* Custom Config */
  var ProgramID = '1111';
  
  /* Default Config */
  var webpack = require('webpack');
  var path = require('path');
  var polyfill = require("babel-polyfill");
  var ExtractTextPlugin = require("extract-text-webpack-plugin");
  
  var BUILD_DIR = path.resolve(__dirname, 'build/Programs/' + ProgramID);
  var APP_DIR = path.resolve(__dirname, 'src/import');
  
  module.exports = {
    entry: [
      'babel-polyfill',
      'webpack-dev-server/client?http://localhost:8080/',
      APP_DIR + '/import.js'
    ],
    output: {
      path: BUILD_DIR + '/',
      filename: '/js/bundle.js',
      publicPath: '../Programs/' + ProgramID
    },
    module: {
      loaders: [{
        test: /\.jsx?$/,
        loaders: ['react-hot', 'babel?presets[]=es2015,presets[]=react,plugins[]=transform-runtime'],
        exclude: /node_modules/
      }, {
        test: /\.css$/,
        loader: ExtractTextPlugin.extract("style-loader", "css-loader")
      }, {
        test: /\.scss$/,
        loaders: ["style", "css", "sass"]
      }, {
        test: /\.(png|woff|woff2|eot|ttf|svg|jpg|gif)$/,
        loader: 'file-loader?name=/images/[name].[ext]'
      }]
    },
    plugins: [
      new ExtractTextPlugin("style.css"),
      new webpack.HotModuleReplacementPlugin(),
      new webpack.NoErrorsPlugin()
    ],
    process: function(path, filename) {
      if (filename.indexOf('node_modules') === -1) {
        path = babelJest.process(path, filename);
        path = webpackAlias.process(path, filename);
      }
      return path;
    },
    externals: {
          "jquery": "jQuery"
      }
  };
  </code></pre>