Closes #45. Add contributor's agreement.

Author: namin

get-involved/index.md

@@ -74,6 +74,12 @@ Typically the scaladoc tool provides a low entry point for new committers, so it
 
 On the Scala bug tracker you will find many bugs that are [marked as good starting points to contributing ("community" bugs)](https://issues.scala-lang.org/secure/IssueNavigator.jspa?requestId=12111) or [that are not currently assigned](https://issues.scala-lang.org/secure/IssueNavigator.jspa?requestId=12112) and that you could pick up. Once you decided on a ticket to look at, see the next step on how to proceed further.
 
+If you are interested in contributing code, we ask you to complete and
+submit to us the
+[Scala Contributor License Agreement](/resources/pdf/contributor_agreement.pdf),
+which allows us to ensure that all code submitted to the project is
+unencumbered by copyrights or patents.
+
 <br/>
 
 ### I have this idea that I'd like to add to Scala, how do I start?
@@ -196,4 +202,4 @@ The files below are recordings of code walk-through sessions by Martin Odersky a
 
 ### Windows
 
--->
+-->