title: How to add multiple .md files to an Angular library package?
body: <p>I created my library well, write README.md, but the documentation is too long to store in one file. So I break it into multiple .md files and now my library structure is like this:</p>
  <pre><code>/projects/my-lib/src/doc/                 documentation .md files
  /projects/my-lib/src/lib/                 project code files
  /projects/my-lib/src/public-api.ts
  /projects/my-lib/src/test.ts
  /projects/my-lib/karma.conf.js
  /projects/my-lib/ng-package.json
  /projects/my-lib/package.json
  /projects/my-lib/README.md                Main page of documentation
  /projects/my-lib/tsconfig.lib.json
  /projects/my-lib/tsconfig.lib.prod.json
  /projects/my-lib/tsconfig.spec.json
  /projects/my-lib/tslint.json
  </code></pre>
  <p>Now in my README.md I use codes like this:</p>
  <pre><code>[Read more](src/doc/a-specific-file.md)
  </code></pre>
  <p>But if I run <code>ng build my-lib</code> the <code>doc</code> folder completly missing from <code>dist/</code> folder.</p>
  <p>How can I say to builder to put my docs into the <code>dist/</code> folder?</p>