Add license header

src/index.js

@@ -1,3 +1,32 @@
+/*
+Copyright (C) 2020 Yarmo Mackenbach
+
+This program is free software: you can redistribute it and/or modify it under
+the terms of the GNU Affero 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 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 <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If your software can interact with users remotely through a computer network,
+you should also make sure that it provides a way for users to get its source.
+For example, if your program is a web application, its interface could display
+a "Source" link that leads users to an archive of the code. There are many
+ways you could offer source, and different solutions will be better for different
+programs; see section 13 for the specific requirements.
+
+You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary. For
+more information on this, and how to apply and follow the GNU AGPL, see <https://www.gnu.org/licenses/>.
+*/
 const validUrl = require('valid-url')
 const { serviceprovidersList, serviceproviders } = require('./serviceproviders')