Bug 1801271 - reference in our source tree doc the Releng Team page on how to add tests for a new config. r=jmaher

With time this will have to be completely moved in tree.

Differential Revision: https://phabricator.services.mozilla.com/D164633

docs/config.yml

@@ -45,6 +45,7 @@ categories:
         - tools/moztreedocs
     testing_doc:
         - testing/automated-testing
+        - testing/tests-for-new-config
         - testing/intermittent
         - testing/testing-policy
         - testing/ci-configs

testing/docs/tests-for-new-config/index.rst

@@ -0,0 +1,5 @@
+Turning on Firefox tests for a new configuration
+================================================
+
+If you want to turn on tests for a new config, there is an excellent detailed
+presentation of the official `Releng Team Page <https://docs.mozilla-releng.net/en/latest/gecko_tests/new_config.html>`__