add section on submitting code in CONTRIBUTING.md
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 6b159581..98db40a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -134,6 +134,13 @@
message explaining that specific commit, or squash your commits into one single checkin with a
detailed message before sending the pull request.
+To submit your changes to the `master` branch, use one of the following methods:
+
+* Wait for one of the project maintainers to submit it for you
+* Click the green "Merge pull request" button on the GitHub UI of your pull
+ request (requires commit access)
+* `git push upstream name_of_your_branch:master` (requires commit access)
+
You must complete the
[Contributor License Agreement](https://cla.developers.google.com/clas).
You can do this online, and it only takes a minute.
