[real-world uses] Add CodeMirror-Record (codemirror#6360)

Author: haoranyu

doc/realworld.html

@@ -52,6 +52,7 @@ <h2>CodeMirror real-world uses</h2>
       <li><a href="http://codefights.com/">CodeFights</a> (practice programming)</li>
       <li><a href="https://github.com/angelozerr/CodeMirror-Eclipse">CodeMirror Eclipse</a> (embed CM in Eclipse)</li>
       <li><a href="http://emmet.io/blog/codemirror-movie/">CodeMirror movie</a> (scripted editing demos)</li>
+      <li><a href="https://github.com/haoranyu/codemirror-record/">CodeMirror Record</a> (codemirror activity recording and playback)</li>
       <li><a href="http://code.google.com/p/codemirror2-gwt/">CodeMirror2-GWT</a> (Google Web Toolkit wrapper)</li>
       <li><a href="http://www.crunchzilla.com/code-monster">Code Monster</a> & <a href="http://www.crunchzilla.com/code-maven">Code Maven</a> (learning environment)</li>
       <li><a href="http://codepen.io">Codepen</a> (gallery of animations)</li>