Rework installation instructions

- Add note on installation being optional
- Add some instruction how to create app shortcut for Chrome

index.html

@@ -158,8 +158,12 @@ $ openssl req -nodes -newkey rsa:4096 -keyout relay.pem -x509 -days 365 -out rel
             </div>
             <div id="collapseFour" class="panel-collapse collapse">
               <div class="panel-body">
+                <p>You don't need to install anything to use this app, it should work with any modern browser. Start using it <a data-toggle="collapse" data-parent="#accordion" href="#collapseOne">right now</a>! However, there are a few ways to improve integration with your operating system.</p>
+                <h3>Firefox</h3>
                 <p>If you have a recent version of Firefox you can install glowing bear as an app. Click the button to install.</p>
-                <button class="btn btn-lg btn-primary" ng-click="install()">Install app <i class="glyphicon glyphicon-chevron-right"></i></button>
+                <button class="btn btn-lg btn-primary" ng-click="install()">Install Firefox app <i class="glyphicon glyphicon-chevron-right"></i></button>
+                <h3>Chrome</h3>
+                <p>To install glowing bear as an app in Chrome, select <kbd>Menu - Add to home screen</kbd> (Android) or <kbd>Menu - Tools - Create Application Shortcuts</kbd> (desktop version).</p>
               </div>
             </div>
           </div>