title: Installing yii2 via composer and it keeps prompting for a password
body: <p>I am just following instructions from the yii website and don't really understand composer. I followed the instructions from here <a href="http://www.yiiframework.com/doc-2.0/guide-start-installation.html" rel="nofollow">http://www.yiiframework.com/doc-2.0/guide-start-installation.html</a></p>
  
  <p>The authentication seems to be working but then it prompts me for the username/password again and again.</p>
  
  <p>Anyone got some things I can check to see why it keeps prompting?</p>
  
  <pre><code>[root@dndbox html]# composer create-project --prefer-dist --stability=dev yiisoft/yii2-app-basic basic
  Installing yiisoft/yii2-app-basic (dev-master b528289495bf9721d2b8c628d69caad42e45b0ce)
    - Installing yiisoft/yii2-app-basic (dev-master master)
      Downloading: connection...
  Could not fetch https://api.github.com/repos/yiisoft/yii2-app-basic/zipball/b528289495bf9721d2b8c628d69caad42e45b0ce, enter your GitHub credentials to go over the API rate limit
  The credentials will be swapped for an OAuth token stored in /root/auth.json, your password will not be stored
  To revoke access to this token you can visit https://github.com/settings/applications
  Username: *.com
  Password: 
  An existing OAuth token for Composer is present and will be reused
  
  Could not fetch https://api.github.com/authorizations, enter your GitHub credentials to go over the API rate limit
  The credentials will be swapped for an OAuth token stored in /root/auth.json, your password will not be stored
  To revoke access to this token you can visit https://github.com/settings/applications
  Username: *.com
  Password: 
  An existing OAuth token for Composer is present and will be reused
  
  Could not fetch https://api.github.com/authorizations, enter your GitHub credentials to go over the API rate limit
  The credentials will be swapped for an OAuth token stored in /root/auth.json, your password will not be stored
  To revoke access to this token you can visit https://github.com/settings/applications
  Username: 
  </code></pre>
  
  <p>==================================== EDIT 1 =====================================</p>
  
  <p>If I visit the URL provided I get a error message in the json,  <a href="https://api.github.com/authorizations" rel="nofollow">https://api.github.com/authorizations</a></p>
  
  <pre><code>{
    "message": "API rate limit exceeded for xxx.xxx.xxx.26. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.)",
    "documentation_url": "https://developer.github.com/v3/#rate-limiting"
  }
  </code></pre>