modify LICENSE and readme

LICENSE

@@ -1,2 +1,16 @@
-本製品をインストール、または使用することによって、お客様は利用規約（
-https://b00st.io/regulations.html）より拘束されることに承諾されたものとします。利用規約に同意されない場合、Boostnoteは、お客様に本製品のインストール、使用のいずれも許諾できません。
+Boostnote - the simplest note app
+
+Copyright (C) 2016 MAISIN&CO.
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU 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 General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.