Add the GPL header for Diopser

README.md

@@ -26,7 +26,7 @@ There are currently no automated builds available, so check the
 [building](#building) section for instructions on how to compile these plugins
 yourself.
 
-- [**diopser**](plugins/diopser) is a totally original phase rotation plugin.
+- [**Diopser**](plugins/diopser) is a totally original phase rotation plugin.
   Useful for oomphing up kickdrums and basses, transforming synths into their
   evil phase-y cousin, and making everything sound like a cheap Sci-Fi laser
   beam.

plugins/diopser/src/lib.rs

@@ -1,3 +1,19 @@
+// Diopser: a phase rotation plugin
+// Copyright (C) 2021-2022 Robbert van der Helm
+//
+// 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 <https://www.gnu.org/licenses/>.
+
 #[macro_use]
 extern crate nih_plug;