docs: updated readme for 2u/release contributions (#3927)

docs: add decision record for master branch split

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,3 +1,7 @@
+# ⛔️ MAIN BRANCH WARNING! 2U EMPLOYEES must make branches against the 2u/main BRANCH
+
+- [ ] I have checked the branch to which I would like to merge.
+
 # ⛔️ DEPRECATION WARNING
 
 **This repository is deprecated and in maintainence-only operation while we work on a replacement, please see [this announcement](https://discuss.openedx.org/t/deprecation-removal-ecommerce-service-depr-22/6839) for more information.**

README.rst

@@ -30,9 +30,11 @@ The code in this repository is licensed under version 3 of the AGPL unless other
 How To Contribute
 -----------------
 
-Anyone merging to this repository is expected to `release and monitor their changes <https://openedx.atlassian.net/wiki/spaces/RS/pages/1835106870/How+to+contribute+to+our+repositories>`__; if you are not able to do this DO NOT MERGE, please coordinate with someone who can to ensure that the changes are released.
+Notice: Internal 2U contributions should be made against the ``2u/main`` branch.  Open source contributions should continue to be made against the ``master`` branch.
 
-Please also read `How To Contribute <https://github.com/openedx/.github/blob/master/CONTRIBUTING.md>`__.
+Anyone merging to the ``2u/main`` branch of this repository is expected to `release and monitor their changes <https://2u-internal.atlassian.net/wiki/spaces/RS/pages/7963261/How+to+contribute+to+our+repositories>`__ (2U-private link); if you are not able to do this DO NOT MERGE, please coordinate with someone who can to ensure that the changes are released.
+
+Please also read `How To Contribute <https://github.com/openedx/.github/blob/master/CONTRIBUTING.md>`__. Even though it was written with ``edx-platform`` in mind, these guidelines should be followed for Open edX code in general.
 
 Reporting Security Issues
 -------------------------

docs/decisions/0008-master-branch-split.rst

@@ -0,0 +1,52 @@
+8. Master branch split from 2u/main
+------------------------------------------------------------
+
+Status
+------
+
+Accepted
+
+Context
+-------
+
+Both 2U and the Open edX community use ecommerce's master branch for releases. Occasionally, changes
+specific to 2U's business case are merged into code, which also influences the structure
+of the code that the community runs, even if the changes are not relevant or beneficial
+to the community at large.
+
+Additionally, 2U has internal compliance checks that can slow the release cycle of
+major changes to ecommerce (for example, the upgrade to Django 4.2). This puts the Open edX community at risk of releasing
+with deprecated packages.
+
+Decision
+--------
+
+A new protected branch will be created named "2u/main", which 2U will continue to use
+as its own main branch, while leaving the "master" branch for use by the community.
+
+Consequences
+------------
+
+This allows the community to move forward with contributions on "master" without risk of
+breaking functionality for 2U or 2U committing changes to "master" that are irrelevant or
+otherwise inappropriate for the community's use case.
+
+Because protected branches in ecommerce require a user with Write access to the repository,
+the "master" branch will now require someone from the community to review and manage
+code contributions to that branch.
+
+Rejected Alternatives
+---------------------
+
+Repo fork
+~~~~~~~~~
+
+Why not fork the repo entirely? 2U and the community use a shared set of tools for
+working in development environments. While working from separate branches and repo
+forks are functionally equivalent, working in separate branches allows for
+minimal updates to shared tooling to support this change. One can simply checkout a
+branch name, without needing the tooling to be updated to know about non-openedx
+git remotes.
+
+This is not a one way door, and if we decide later the a proper repo fork is a better
+solution, then we are open to making adjustments.