license refined

renkun-ken · renkun-ken · commit bf17aa729f47 · 2014-04-04T10:59:12.000+08:00
diff --git a/LICENSE.md b/LICENSE.md
@@ -3,3 +3,5 @@
 This tutorial is only for educational use and should not be used for commercial purpose.
 
 The `{nutshell}` package is under [CC BY-NC-ND 3.0 US](http://creativecommons.org/licenses/by-nc-nd/3.0/us/) license.
+
+The `{hflights}` package and the dataset in it are under [CC0](http://creativecommons.org/publicdomain/zero/1.0/legalcode) license.
