diff --git a/LICENSE.txt b/LICENSE.txt
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--- /dev/null
+++ b/LICENSE.txt
@@ -0,0 +1,13 @@
+Copyright 2020 Felix Bartels
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License, version 3,
+as published by the Free Software Foundation.
+
+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 Affero General Public License for more
+details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see http://www.gnu.org/licenses/.