Add copying section

README.org

@@ -20,3 +20,16 @@ This toggles bold text for priority items in agenda view.
 ** Acknowledgement
 - [[https://github.com/konrad1977/kanagawa-emacs][konrad1977/kanagawa-emacs]]
 - [[https://github.com/rebelot/kanagawa.nvim][rebelot/kanagawa.nvim]]
+** Copying
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program. If not, see <https://www.gnu.org/licenses/>.