add entry in changelog
@@ -18,6 +18,12 @@ The format is based on `Keep a Changelog`_.
`UNRELEASED`_
=============
+Added
+-----
+
+- Relative-Phase Toffoli gates ``rccx`` (with 2 controls) and ``rcccx`` (with 3 controls).
+
+
`0.5.0`_ - 2019-05-02
=====================
