Retwis ported to modern Redis data types.

The example (and related documentation at redis.io) was not updated for
5 years. Redis had no sorted sets and hashes when the original code was
written (!). An update was really needed.

We also use a modern PHP client now: Predis. A copy is shipped within
this repository to make life easier to newcomers trying Redis for the
first time via this example.

timeline.php

@@ -0,0 +1,14 @@
+<?
+include("retwis.php");
+include("header.php");
+?>
+<h2>Timeline</h2>
+<i>Latest registered users (an example of sorted sets)</i><br>
+<?
+showLastUsers();
+?>
+<i>Latest 50 messages from users aroud the world!</i><br>
+<?
+showUserPosts(-1,0,50);
+include("footer.php")
+?>