README: mention license

README.adoc

@@ -24,6 +24,8 @@ Authorization is based on user name (option `Users`) or UNIX group membership
 Additional methods can be implemented easily. Have a look at `config.go` and
 `isNetworkUserAccesible()` in `main.go`.
 
+WOLASS is free software and licensed under GPL version 3 or later.
+
 
 == Screenshot
 
@@ -82,3 +84,23 @@ IdpMetadata = """
 ...
 """
 ....
+
+
+== License
+
+This program is licensed under GPL version 3 or later.
+
+Copyright (C) 2022  Simon Ruderich
+
+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/>.