add extension support to the CRLBuilder
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 859bc83..e4711be 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -822,6 +822,16 @@
:param time: The :class:`datetime.datetime` object (in UTC) that marks
the next update time for this CRL.
+ .. method:: add_extension(extension, critical)
+
+ Adds an X.509 extension to this CRL.
+
+ :param extension: An extension with the
+ :class:`~cryptography.x509.ExtensionType` interface.
+
+ :param critical: Set to ``True`` if the extension must be understood and
+ handled by whoever reads the CRL.
+
.. method:: sign(private_key, algorithm, backend)
Sign this CRL using the CA's private key.