title: devDependencies "module not found" error
body: <p>I separated my dependencies between <code>devDependencies</code> and <code>dependencies</code></p>
  
  <pre><code>{
    "name": "contenttype",
    "version": "1.0.0",
    "description": "",
    "main": "index.js",
    "scripts": {
      "test": "echo \"Error: no test specified\" &amp;&amp; exit 1"
    },
    "author": "",
    "license": "ISC",
    "dependencies": {
      "react": "^15.3.2",
      "react-dom": "^15.3.2"
    },
    "scripts": {
      "dev": "webpack-dev-server --content-base src --inline --hot"
    },
    "devDependencies": {
      "babel-core": "^6.18.2",
      "babel-loader": "^6.2.7",
      "babel-preset-es2015": "^6.18.0",
      "babel-preset-react": "^6.16.0",
      "webpack": "^1.13.3"
    }
  }
  </code></pre>
  
  <p>As you can see I have an <code>npm</code> script, but when I run <code>npm run dev</code>, I get the error </p>
  
  <pre><code>webpack module not found
  </code></pre>
  
  <p>Why is that? The webpack module is in my <code>devDependencies</code>, so why isn't it being recongnized?</p>