title: Add Angular Material to a custom library
body: <p>I want to write my own library and reuse it in other projects, so I created a new app and generated a library there:</p>
  
  <pre><code>ng new lib-collection
  cd lib-collection
  ng g library first-lib --prefix va
  </code></pre>
  
  <p>How to add Angular Material to my library? I wanted to use something like this:</p>
  
  <pre><code>ng add @angular/material --project=first-lib
  </code></pre>
  
  <p>But I got an error: <code>Could not find the project main file inside of the workspace config (projects/first-lib/src)</code>. What's wrong?</p>