title: Error in firebase-admin on Angular 2
body: <p>I need to use <code>firebase-admin</code> to create a token to authenticate in firebase (have another way?). But when I try to use, I receive the error that <code>jsonwebtoken</code> module is not found, then I install this module. After, I this, I receive the error <code>node-purge</code> module not found, then I install this. And the two error is fixed, but appears a third: <code>cannot read property map of null</code>.</p>
  
  <p>What I do? Have another way to make tokens for firebase?</p>