Improve documentation for utils.default_tzinfo
diff --git a/docs/utils.rst b/docs/utils.rst
new file mode 100644
index 0000000..5f36591
--- /dev/null
+++ b/docs/utils.rst
@@ -0,0 +1,6 @@
+=====
+utils
+=====
+.. automodule:: dateutil.utils
+   :members:
+   :undoc-members: