add a link to the v0.5.0 in the index

Author: jube

index.html

@@ -30,6 +30,13 @@ <h1>Gamedev Framework (gf)</h1>
 
         <h2>Releases</h2>
 
+        <h3>gf 0.5.0 (14 Jul 2017)</h3>
+
+        <ul>
+          <li><a href="v0.5.0">Documentation for gf 0.5.0</a></li>
+          <li><a href="https://github.com/GamedevFramework/gf/archive/v0.5.0.tar.gz">Source code for gf 0.5.0</a></li>
+        </ul>
+
         <h3>gf 0.4.0 (14 Apr 2017)</h3>
 
         <ul>