Updated changelog with _trans_depth fix.
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index de2b366..b9ca39c 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -57,6 +57,7 @@
 -  Unlink raised an error if cache file did not exist when you try to delete it.
 -  Fixed a bug (#181) where a mis-spelling was in the form validation
    language file.
+-  Fixed a bug (#159, #163) that mishandled Active Record nested transactions because _trans_depth was not getting incremented.
 
 
 Version 2.1.0