title: Firebase types and no-implicit-dependencies with default tslint.json
body: <p>After reading the newest Firebase blog post <a href="https://firebase.googleblog.com/2018/01/why-you-should-use-typescript-for.html" rel="noreferrer">Why you should use TypeScript for writing Cloud Functions</a>, I decided to try <code>tslint</code> and it's amazing, though I have a problem with my types.</p>
  
  <p>I have an import statement as this</p>
  
  <pre><code>import { DocumentSnapshot, DocumentReference, QuerySnapshot, WriteResult, Transaction, WriteBatch } from '@google-cloud/firestore';
  </code></pre>
  
  <p>But even though my code is working fine tslint tells me the following.</p>
  
  <blockquote>
    <p>[tslint] Module '@google-cloud/firestore' is not listed as dependency in package.json (no-implicit-dependencies)</p>
  </blockquote>
  
  <p>What is the best practice with Firebase + TypeScript for using/importing types?</p>