title: When I install electron on mac i have got permission denied message
body: <pre><code>  MacdeMacBook-Air-5:electron-api-demos Mac$ sudo npm install
  
  &gt; electron-chromedriver@1.6.0 install /usr/local/yanxi/electron-api-demos/node_modules/electron-chromedriver
  &gt; node ./download-chromedriver.js
  
  /usr/local/yanxi/electron-api-demos/node_modules/electron-chromedriver/download-chromedriver.js:16
    if (error != null) throw error
                       ^
  
  Error: EACCES: permission denied, mkdir '/usr/local/yanxi/electron-api-demos/node_modules/electron-chromedriver/electron-tmp-download-7487-1515139845145'
  npm ERR! code ELIFECYCLE
  npm ERR! errno 1
  npm ERR! electron-chromedriver@1.6.0 install: `node ./download-chromedriver.js`
  npm ERR! Exit status 1
  npm ERR! 
  npm ERR! Failed at the electron-chromedriver@1.6.0 install script.
  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
  
  npm ERR! A complete log of this run can be found in:
  npm ERR!     /Users/Mac/.npm/_logs/2018-01-05T08_10_45_423Z-debug.log
  </code></pre>
  
  <p>It show that I have no permission
  I have try many methord to solve this problem but do not work!
  I have  use cmd :
   <code>sudo chmod 777 .</code>
   <code>sudo chown -R nodody:nobody ./*</code></p>
  
  <p>Attention: I did it on mac platform!</p>