add project manager to 4.0 release notes (#1071)

Add project manager to 4.0 release notes.

source/release-notes/v4.0-release-notes.rst

@@ -318,6 +318,22 @@ The figure below is an image of how the file editor appears in 4.0.
 .. figure:: /images/4.0_file_editor.png
    :alt: An image showing the file editor as it appears in 4.0 with the Open OnDemand navigation bar and a new panel to the left for saving and other file editor specific options.
 
+
+Project Manager Preview
+.......................
+
+The Open OnDemand development team has been working on a replacement for the Job
+Composer. We're calling this new application the Project Manager.
+
+While version 3.1 also shipped with a preview of this application, we've made
+several updates since then. The Project Manager is disabled by default because
+it's not feature rich enough to replace the Job Composer in this release.
+
+However, you may still wish to enable this for staff members or friendly users.
+
+To enable the Project Manager, simply follow the instructions in :ref:`disabling_applications`
+to enable this application.
+
 Upgrade Instructions
 --------------------