Add CLA paragraph
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c2b3a43..4a7b952 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -10,6 +10,11 @@
Bug Fixes and New Features
--------------------------
+As your first step, please visit and read the [Contributor License Agreement]
+(http://prediction.io/cla). All contributors are required to sign this
+agreement.
+
+
Before starting to write code, look for existing [tickets]
(https://predictionio.atlassian.net/browse/SDKRUBY) or [create one]
(https://predictionio.atlassian.net/secure/CreateIssue!default.jspa)