Add AGPLv3 licensing

README.md

@@ -71,6 +71,35 @@ HTTP-specific parts of mail to be served via reverse proxying. This includes:
 
 Probably other stuff. Email is big, and just keeps getting bigger.
 
+## Licensing
+
+Copyright (C) 2018 Nick Thomas <crockery@ur.gs>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of version 3 of the GNU Affero General Public License
+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 <https://www.gnu.org/licenses/>.
+
+## Contributing
+
+Contributions are very welcome. Feel free to open a merge request against
+[the GitLab hosted project](https://gitlab.com/lupine/crockery), or to email
+patches or a link to a hosted git branch, directly to the author.
+
+To be accepted, contributions must:
+
+* Accept copyright assignment to the author
+* Be licensed according to the foregoing terms
+* Consist entirely of [signed commits](https://git-scm.com/book/en/v2/Git-Tools-Signing-Your-Work)
+* Indicate acceptance of the above with a `Signed-off-by:` line in each commit message
+
 ## How
 
 ### Building a binary