Adding some update notes for 3.0.0 (renaming AR to QB)
diff --git a/user_guide_src/source/installation/upgrade_300.rst b/user_guide_src/source/installation/upgrade_300.rst
index 4c594ab..e434e8d 100644
--- a/user_guide_src/source/installation/upgrade_300.rst
+++ b/user_guide_src/source/installation/upgrade_300.rst
@@ -31,3 +31,13 @@
 
 Use of the `$autoload['core']` config array has been deprecated as of CodeIgniter 1.4.1 and is now removed.
 Move any entries that you might have listed there to `$autoload['libraries']` instead.
+
+Step 4: Update your config/database.php
+=======================================
+
+Due to 3.0.0's renaming of Active Record to Query Builder, inside your _config/database.php_, you will
+need to rename the `$active_record` variable to `$query_builder`.
+
+    $active_group = 'default';
+    // $active_record = TRUE;
+    $query_builder = TRUE;
\ No newline at end of file