add contributor agreement

AUTHORS

@@ -1,11 +1,43 @@
+Contributor Agreement
+=====================
+
+The submitter agrees by adding his or her name within the section below named
+"Contributors" and submitting the resulting modified document to the
+canonical shared repository location for this software project (whether
+directly, as a user with "direct commit access", or via a "pull request"), he
+or she is signing a contract electronically.  The submitter becomes a
+Contributor after a) he or she signs this document by adding their name
+beneath the "Contributors" section below, and b) the resulting document is
+accepted into the canonical version control repository.
+
+By submitting any code, documentation, modifications, or other contributions
+(each a “Contribution”) to the project, you represent, warrant and agree that:
+1. The Contributions are hereby licensed to the under the terms of the
+   BSD 2-clause License (https://opensource.org/licenses/BSD-2-Clause).
+2. You are the sole author and owner of each of your Contributions, you have
+   the right to grant the license in Section 1, and projects exercise of such
+   license will not infringe your or, to your knowledge, any other
+   party’s intellectual property rights.
+3. Project may freely assign and transfer this Contributor License Agreement
+   to any third party.
+
+
+List of Contributors
+====================
+
+The below-signed are contributors to a code repository that is part of the
+project.  Each below-signed contributor has read,
+understand and agrees to the terms above in the section within this document
+entitled "Contributor Agreement" as of the date beside his or her name.
+
 Current or previous core committers:
 
-* Marcin Lulek (Ergo^)
+* Marcin Lulek (Ergo^) 2000-01-01
 
 Contributors:
 
 * Luke Crooks (crooksey)
 * Svintsov Dmitry (uralbash)
 * Marcin Kuzminski (marcinkuzminski)
 * Lukasz Fidosz (virhilo)
-* Arian Maykon de Araújo Diógenes (arianmaykon)
+* Arian Maykon de Araújo Diógenes (arianmaykon)