Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -9,7 +9,7 @@ We actively welcome your pull requests.
 2. If you've added code that should be tested, add tests.
 3. If you've changed APIs, update the documentation.
 4. Ensure the test suite passes.
-5. Make sure your code lints.
+5. Make sure your code lints by running `./format.sh`
 6. If you haven't already, complete the Contributor License Agreement ("CLA").
 
 ## Contributor License Agreement ("CLA")
@@ -28,4 +28,4 @@ outlined on that page and do not file a public issue.
 
 ## License
 By contributing to OrienterNet, you agree that your contributions will be licensed
-under the LICENSE file in the root directory of this source tree.
\ No newline at end of file
+under the LICENSE file in the root directory of this source tree.