Added a note about build triggers [ci skip]

doc/ci/triggers/README.md

@@ -2,6 +2,10 @@
 
 > [Introduced][ci-229] in GitLab CE 7.14.
 
+> **Note**:
+GitLab 8.12 has a completely redesigned build permissions system.
+Read all about the [new model and its implications][../../user/project/new_ci_build_permissions_model.md#build-triggers].
+
 Triggers can be used to force a rebuild of a specific branch, tag or commit,
 with an API call.
 

doc/user/project/new_ci_build_permissions_model.md

@@ -277,5 +277,13 @@ test:
     - docker run $CI_REGISTRY/group/other-project:latest
 ```
 
+### Build triggers
+
+> **Note:**
+Currently Build triggers do not support the new permission model.
+They continue to use the old authentication mechanism where the CI build
+can access only own sources. We plan to remove that limitation in one of the upcoming releases.
+
+
 [git-scm]: https://git-scm.com/book/en/v2/Git-Tools-Submodules
 [build permissions]: ../permissions.md#builds-permissions