Add howto for moving issues and PRs, to README

---------

Co-authored-by: Johanna England <johanna.england@sikt.no>

README.rst

@@ -12,17 +12,103 @@ See `argus-server`_ for more about argus.
 Imports `django-htmx`_. See the `documentation for django-htmx`_
 for details.
 
-.. attention::
+Moving to argus-server repo
+---------------------------
+This repo is in the process of being merged into the repo at `argus-server`_.
 
-   This repo is in the process of being merged into the repo at `argus-server`_.
+New issues and PRs should be opened against that repo, not this one.
+Existing PRs will be merged here, then moved. Existing open issues will
+also be moved (eventually).
+
+Moving issues
+~~~~~~~~~~~~~
+
+Github seems to be able to handle this just fine.
+
+Moving PRs
+~~~~~~~~~~
+
+Procedure for existing PRs:
+
+The code tree has been changed from ``src/argus_htmx`` to ``src/argus/htmx``
+so branches should be updated accordingly. Try ``git mv`` or ``git rebase``.
+
+If you want to move the PR to the argus-server repo you first need to move the
+branch, then start a new PR with the same name at argus-server, then link back
+to any discussion in this repo from the new PR. Now you can close the PR in
+this repo.
+
+First, setup the remote.
+
+1. Add `argus-server`_ as a remote::
+
+        git remote add argus git@github.com:Uninett/Argus.git
+
+2. Fetch the branches on argus::
+
+        git fetch argus
+
+3. Checkout master::
+
+        git switch master
+
+Second, prep the branch.
+
+Make sure the files are in the right tree, ``src/argus/htmx``. ``src/argus``
+*in this repo* has no ``__init__.py``, this is to avoid conflicts. Do not add
+one. Do ``git mv src/argus_htmx src/argus/htmx`` or ``git rebase main
+mybranch`` or use a graphical client to cherrypick one by one onto main. It is
+enough to just move the files. Correcting import paths and file include paths
+can be done *after* the move, in the new repo, with a new commit.
+
+This way, you can deal with file renaming conflicts once, and content change
+conflicts once.
+
+Now you're ready for the move.
+
+1. Make a temporary branch name for the branch you want to move, at its head::
+
+        git switch mybranch
+        git switch -c fvgyhj
+
+2. If it's only a single commit you can cherrypick it. Move the real name to
+   the master then cherry-pick::
+
+        git branch -f mybranch master
+        git switch mybranch
+        git cherry-pick fvgyhj
+
+   If not, a rebase can do it for you. If you didn't do step 1 correctly there
+   will be more conflicts than necessary!
+
+   How to rebase (assumes ``mybranch`` is rebased on ``main``)::
+
+        git rebase --onto master main mybranch
+
+   You can now remove the temporary branch::
+
+        git branch -d fvgyhj
+
+3. Push the branch to the new remote::
+
+        git switch mybranch
+        git push argus
+
+4. Make the PR in argus-server and pull the branch in your local copy of that
+   repo.
+
+5. Do any internal changes to the actual code in the new repo if you didn't do
+   that as a part of the branch prep.
+
+Done!
 
-   New issues and PR's should be opened agains that repo, not this one.
-   Existing PR's will be merged here, then moved. Existing open issues will
-   also be moved (eventually).
 
 How to play
 ===========
 
+See the docs of argus-server. The rest of this README is deprecated but kept
+here until everything has been moved.
+
 Install
 -------