title: How to add custom font sizes to QuillJS editor
body: <p>How do you add custom font sizes to the toolbar with QuillJS? I've tried two approaches:</p>
  
  <pre><code>// Initiate the editor
          let toolbarOptions = [
              ['bold', 'italic', 'underline', 'strike'],
              [{ 'align': [] }],
              [{ 'size': ['10px', '20px', '80px'] }],
              [{ 'color': ['#FFF'] }]
          ];
          this.editor = new Quill('#executive-control-editor', {
              modules: {
                  toolbar: toolbarOptions
              },
              theme: 'snow'
          });
  </code></pre>
  
  <p>and</p>
  
  <pre><code>&lt;div id="toolbar"&gt;
          &lt;span class="ql-formats"&gt;
              &lt;button class="ql-bold"&gt;&lt;/button&gt;
              &lt;button class="ql-italic"&gt;&lt;/button&gt;
              &lt;button class="ql-underline"&gt;&lt;/button&gt;
              &lt;button class="ql-strike"&gt;&lt;/button&gt;
          &lt;/span&gt;
          &lt;span class="ql-formats"&gt;
              &lt;select class="ql-align"&gt;&lt;/select&gt;
          &lt;/span&gt;
          &lt;span class="ql-format-group"&gt;
            &lt;select title="Size" class="ql-size"&gt;
              &lt;option value="10px"&gt;Small&lt;/option&gt;
              &lt;option value="13px"&gt;Normal&lt;/option&gt;
              &lt;option value="18px"&gt;Large&lt;/option&gt;
              &lt;option value="32px"&gt;Huge&lt;/option&gt;
            &lt;/select&gt;
          &lt;/span&gt;
          &lt;span class="ql-formats"&gt;
              &lt;button class="ql-image"&gt;&lt;/button&gt;
          &lt;/span&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>However neither of them work. Is there something I'm missing here? I've tried removing the <strong>"px"</strong> from the value as well; still nothing.</p>