Merge pull request #16 from opencomponents/add-guestline

Add guestline to who's using OC

Author: ricardo-devis-agullo

assets/guestline.png

@@ -151,6 +151,9 @@ <h1>Who's using OC?</h1>
       <a href="https://alvarium.io/">
         <img src="./assets/alvarium.png" alt="Alvarium">
       </a>
+      <a href="https://www.guestline.com/">
+        <img src="./assets/guestline.png" alt="Guestline" />
+      </a>
     </div>
   </article>