Add URL scheme note

Author: mythz

src/wwwroot/gfm/apps/02.html

@@ -14,9 +14,10 @@
 <a href="https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/sql/linq/downloading-sample-databases" rel="nofollow">Northwind</a> and
 <a href="https://www.sqlitetutorial.net/sqlite-sample-database/" rel="nofollow">Chinook</a> SQLite databases which after installing the latest
 <a href="https://docs.servicestack.net/netcore-windows-desktop" rel="nofollow">app</a> dotnet tool:</p>
-<pre><code>$ dotnet tool install -g app    
+<pre><code>$ dotnet tool install -g app
+$ app -version
 </code></pre>
-<p>Can be run from the link below in a Windows x64 Desktop App:</p>
+<p>First time <code>app</code> is run it registers the <a href="#app-url-schemes">app:// URL scheme</a> allowing Windows x64 Desktop Apps to be launched from URLs:</p>
 <ul>
     <li><strong><a name="app://sharpdata?mix=northwind.sharpdata">app://sharpdata?mix=northwind.sharpdata</a></strong></li>
     <li><strong><a name="app://sharpdata?mix=chinook.sharpdata">app://sharpdata?mix=chinook.sharpdata</a></strong></li>

src/wwwroot/gfm/apps/02.md

@@ -18,9 +18,10 @@ For an example of this in action we've published customized gists for the
 [Chinook](https://www.sqlitetutorial.net/sqlite-sample-database/) SQLite databases which after installing the latest 
 [app](https://docs.servicestack.net/netcore-windows-desktop) dotnet tool:
 
-    $ dotnet tool install -g app    
+    $ dotnet tool install -g app
+    $ app -version
 
-Can be run from the link below in a Windows x64 Desktop App:
+First time `app` is run it registers the [app:// URL scheme](#app-url-schemes) allowing Windows x64 Desktop Apps to be launched from URLs:
 
 <ul>
     <li><strong><a name="app://sharpdata?mix=northwind.sharpdata">app://sharpdata?mix=northwind.sharpdata</a></strong></li>