Update CONTRIBUTING.md
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 488d614..d2c2c50 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -45,6 +45,7 @@
* `gclient sync` This will fetch all the source code that Flutter depends on. Avoid interrupting this script, it can leave your repository in an inconsistent state that is tedious to clean up.
* `cd src` (Change to the directory that `gclient sync` created in your `flutter` directory)
* `git remote add upstream git@github.com:flutter/engine.git` (So that you fetch from the master repository, not your clone, when running `git fetch` et al)
+ * Add `.../flutter/src/third_party/dart-sdk/dart-sdk/bin/` to your path so that you can run the `pub` tool more easily.
Building the code
-----------------
