Add Copyright & License notice to README.md

Author: ktprograms

README.md

@@ -1,5 +1,26 @@
 # WaterTracker
 
+GNU General Public License v3.0
+
+Copyright (c) 2020 Toh Jeen Gie Keith
+
+<hr/>
+
+This file is part of WaterTracker.
+
+WaterTracker 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.
+
+WaterTracker 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 WaterTracker.  If not, see <https://www.gnu.org/licenses/>.
+
 ## About
 WaterTracker is a simple app that reminds you to drink water!