feat: add gplv3 license

include/threadpool.h

@@ -1,3 +1,20 @@
+/**
+ * sci - a simple ci system
+   Copyright (C) 2024 Asger Gitz-Johansen
+
+    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/>.
+ */
 #ifndef SCI_THREADPOOL_H
 #define SCI_THREADPOOL_H
 #include "optional.h"