title: ng build can't find index.ts which exists
body: <p>I installed <a href="https://www.npmjs.com/package/ngx-embed-video" rel="nofollow noreferrer">ngx-embed-video</a> as told on the documentation and it works with ng serve.</p>
  
  <p>The problem, when I try to build the project, I encounter the following error. Error says index.ts doesn't exists but it exists.</p>
  
  <pre><code>/my-workpath/node_modules/ngx-embed-video/index.ts is missing from the TypeScript compilation. Please make sure it is in your tsconfig via the 'files' or 'include' property.
  </code></pre>
  
  <p>I also removed node_modules and npm build again. It's still the same.</p>
  
  <pre><code>Angular CLI: 6.2.7
  Node: 10.10.0
  OS: darwin x64
  Angular: 6.1.10
  </code></pre>
  
  <p>What's your suggestion? 
  Thank you.</p>