Docs: Replace GitCasts link, add GitHub training

Bug: 27529427
Change-Id: Id6d5fd24e936b42d73daaf6bd060429b36336ce7
diff --git a/src/source/git-resources.jd b/src/source/git-resources.jd
index 0d15bac..39de9e1 100644
--- a/src/source/git-resources.jd
+++ b/src/source/git-resources.jd
@@ -19,6 +19,9 @@
 <p>For further information on Git, check out these excellent off-site resources:</p>
 <ul>
 <li>
+<p><a href="https://training.github.com/">GitHub Training</a></p>
+</li>
+<li>
 <p>The <a href="http://book.git-scm.com">Git Community Book</a> (maintained by Scott Chacon) </p>
 </li>
 <li>
@@ -28,6 +31,8 @@
 <p><a href="http://www.kernel.org/pub/software/scm/git/docs">Git Manual Page</a> </p>
 </li>
 <li>
-<p><a href="http://www.gitcasts.com">GitCasts</a> (Git how-to videos)</p>
+<p><a
+href="https://www.youtube.com/playlist?list=PLttwD7NyH3omQLyVtan0CFOX_UWItX_yG">GitCasts</a>
+(Git how-to videos)</p>
 </li>
 </ul>