Added tests for logging undefined and added it to the docs.
diff --git a/CHANGES b/CHANGES
index 907e1c0..b9606f6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -14,6 +14,8 @@
 - Fixed loop length calculation for some iterators.
 - Changed how Jinja2 enforces strings to be native strings in
   Python 2 to work when people break their default encoding.
+- Added :func:`make_logging_undefined` which returns an undefined
+  object that logs failures into a logger.
 
 Version 2.7.2
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