title: Webpack not building css file
body: <p>So I was following the tutorial on <a href="http://webpack.github.io/docs/tutorials/getting-started/" rel="nofollow">http://webpack.github.io/docs/tutorials/getting-started/</a> and I was stuck on the css style loader step. Here is my entry.js: </p>
  
  <pre><code>require("!style!css!./style.css");
  document.write(require("./content.js"))
  </code></pre>
  
  <p>this is content.js:</p>
  
  <pre><code>module.exports = "It works from content.js";
  </code></pre>
  
  <p>this is style.css:</p>
  
  <pre><code>body{
      background: yellow;
  }
  </code></pre>
  
  <p>After this, I am running this command:</p>
  
  <blockquote>
    <p>webpack ./entry.js bundle.js</p>
  </blockquote>
  
  <p>I am getting this error:</p>
  
  <blockquote>
    <p>Version: webpack 1.13.0 Time: 866ms
        Asset     Size  Chunks             Chunk Names bundle.js  10.1 kB       0  [emitted]  main    [0] ./entry.js 115 bytes {0} [built]    [4]
    ./content.js 45 bytes {0} [built]
        + 3 hidden modules</p>
    
    <p>ERROR in ./~/css-loader!./style.css Module build failed:
    ReferenceError: Promise is not defined
        at LazyResult.async (/var/www/html/webpack/node_modules/css-loader/node_modules/postcss/lib/lazy-result.js:157:31)
        at LazyResult.then (/var/www/html/webpack/node_modules/css-loader/node_modules/postcss/lib/lazy-result.js:79:21)
        at processCss (/var/www/html/webpack/node_modules/css-loader/lib/processCss.js:198:5)
        at Object.module.exports (/var/www/html/webpack/node_modules/css-loader/lib/loader.js:24:2)  @
    ./~/style-loader!./~/css-loader!./style.css 4:14-73</p>
  </blockquote>
  
  <p>How to fix this?</p>