[real-world uses] Add JSER

doc/realworld.html

@@ -96,6 +96,7 @@
       <li><a href="http://extensions.joomla.org/extensions/edition/editors/8723">Joomla plugin</a></li>
       <li><a href="http://jqfundamentals.com/">jQuery fundamentals</a> (interactive tutorial)</li>
       <li><a href="http://jsbin.com">jsbin.com</a> (JS playground)</li>
+      <li><a href="http://tool.jser.com/preprocessor">JSER preprocessor</a></li>
       <li><a href="https://github.com/kucherenko/jscpd">jscpd</a> (code duplication detector)</li>
       <li><a href="http://jsfiddle.com">jsfiddle.com</a> (another JS playground)</li>
       <li><a href="http://www.jshint.com/">JSHint</a> (JS linter)</li>