title: html-webpack-plugin not inject js file into index.html when using webpack-dev-server
body: <p>Here is my webpack config :</p>
  
  <pre><code>var path = require('path');
  var webpack = require('webpack')
  var HtmlWebpackPlugin = require('html-webpack-plugin')
  var fs = require('fs'),buildPath='./dist/';
  var folder_exists = fs.existsSync(buildPath);
  
  if(folder_exists == true)
  {
      require('shelljs/global')
      rm('-rf', 'dist')
  
  };
  
  module.exports = {
  
      entry: './src/main',
  
      output: {
          path: path.join(__dirname, './dist'),
  
          filename: '[name].js',
  
          publicPath: '/dist/'
  
      },
  
  
      devServer: {
          historyApiFallback: true,
          hot: false,
          inline: true,
          grogress: true,
      },
      // "vue-hot-reload-api": "^1.2.2",
  
      module: {
  
          loaders: [
  
              { test: /\.vue$/, loader: 'vue' },
  
              { test: /\.js$/, loader: 'babel', exclude: /node_modules/ },
  
              { test: /\.css$/, loader: 'style-loader!css-loader'},
  
          //install css-loader style-loader sass-loader node-sass --save-dev
              { test: /\.scss$/, loader: 'style!css!sass?sourceMap'},
  
              { test: /\.(png|jpg|gif)$/, loader: 'url-loader?limit=8192&amp;name=images/[name].[ext]'},
  
              { test: /\.(html|tpl)$/, loader: 'html-loader' },
          ]
      },
  
      vue: {
          loaders: {
              js:'babel',
              css: 'style-loader!css-loader',
              sass:'style!css!sass?sourceMap'
          }
      },
  
      babel: {
          presets: ['es2015'],
          plugins: ['transform-runtime']
      },
      plugins:[
         new HtmlWebpackPlugin({
          template: 'index.html',
          filename: './index.html',
          inject:true
         }),
      ],
      resolve: {
  
          extensions: ['', '.js', '.vue'],
  
          alias: {
              filter: path.join(__dirname, './src/filters'),
              components: path.join(__dirname, './src/components')
          }
      },
  
      devtool: 'eval-source-map'
  };
  </code></pre>
  
  <p>And in package.json:</p>
  
  <pre><code>   "scripts": {
      "test": "echo \"Error: no test specified\" &amp;&amp; exit 1",
      "start": "webpack-dev-server --inline",
      "build": "webpack --config webpack.config.prod.js"
    },
  </code></pre>
  
  <p>When I run npm start, in localhost the js file is not injected in <code>index.html</code>.
  If I run webpack or npm run build, the js file is injected successfully.
  Can <code>html-webpack-plugin</code> also inject js file into <code>index.html</code> when I'm in localhost?</p>