title: How to add NODE_PATH to webpack in package.json?
body: <p>How do I add NODE_PATH to webpack in package.json?</p>
  
  <p>Part of my packcage.json:</p>
  
  <pre><code>  "dependencies": {
      "axios": "^0.16.2",
      "cross-env": "^5.0.1",
      "koa": "^2.3.0",
      "koa-mount": "^3.0.0",
      "koa-static": "^4.0.1",
      "koa-trie-router": "^2.1.5",
      "mongodb": "^2.2.31",
      "nuxt": "^1.0.0-rc3",
      "socket.io": "^2.0.3"
    },
    "devDependencies": {
      "babel-eslint": "^7.2.3",
      "backpack-core": "^0.4.1"
    },
    "scripts": {
      "test": "mocha --harmony",
      "dev": "NODE_PATH=./app backpack dev",
      "build": "nuxt build &amp;&amp; backpack build",
      "start": "cross-env NODE_ENV=production NODE_PATH=./app node build/main.js"
    },
  </code></pre>
  
  <p>backpack.config.js:</p>
  
  <pre><code>module.exports = {
    webpack: (config, options, webpack) =&gt; {
      config.entry.main = './server/index.js'
      return config
    }
  }
  </code></pre>
  
  <p>In my server.js:</p>
  
  <pre><code>import Koa from 'koa'
  import { Nuxt, Builder } from 'nuxt'
  import socket from 'socket.io'
  import http from 'http'
  import config from 'config' // this is './config' without NODE_PATH=./app
  </code></pre>
  
  <p><strong>Error</strong> at <code>npm run dev</code>:</p>
  
  <pre><code>This dependency was not found:
  
  * config in ./server/index.js
  </code></pre>
  
  <p>But if I run <code>npm start</code>, it is working fine.</p>
  
  <p>Any ideas?</p>