license note

README.md

@@ -70,3 +70,9 @@ In addition to the core functionality, pybind11 provides some extra goodies:
 
 - Everything is contained in just a few header files; there is no need to link
   against any additional libraries.
+
+### License
+
+pybind11 is provided under a BSD-style license that can be found in the
+``LICENSE.txt`` file. By using, distributing, or contributing to this project,
+you agree to the terms and conditions of this license.