added contributing section to README

README.rst → README.md

@@ -8,5 +8,15 @@ Enrollment data may also be retrieved in the CSV format by changing the data_for
 
 Testing
 =======
+    $ make validate
 
-:code:`$ make validate`
+
+How to Contribute
+-----------------
+
+Contributions are very welcome, but for legal reasons, you must submit a signed
+[individual contributor's agreement](http://code.edx.org/individual-contributor-agreement.pdf)
+before we can accept your contribution. See our
+[CONTRIBUTING](https://github.com/edx/edx-platform/blob/master/CONTRIBUTING.rst)
+file for more information -- it also contains guidelines for how to maintain
+high code quality, which will make your contribution more likely to be accepted.