Merge #1528: docs: add github-merge.py process for merging PRs

8f28d82 docs: add github-merge.py process for merging PRs (Byron Hambly)

Pull request description:

  Documents how to merge PRs using the github-merge.py script from Bitcoin maintainer tools repo.

ACKs for top commit:
  psgreco:
    ACK 8f28d82

Tree-SHA512: b263dd7715fa71926ceeae053e453a4a19b64fa89c88cb0f84fa15bafbcc1051f35ca4f28a05f41dfc8d3af1d1de9eb2bb6cd832867cf7d7d7772a3c7267777b

Author: psgreco

doc/github-merge-script.md

@@ -0,0 +1,68 @@
+# github-merge.py
+
+Please use this python script from the [Bitcoin maintainer tools](https://github.com/bitcoin-core/bitcoin-maintainer-tools/) repo for merging PRs.
+
+- Clone the repo and copy or just download the [github-merge.py](https://github.com/bitcoin-core/bitcoin-maintainer-tools/blob/main/github-merge.py) script into a directory on your $PATH.
+
+```
+wget https://raw.githubusercontent.com/bitcoin-core/bitcoin-maintainer-tools/refs/heads/main/github-merge.py -O ~/.local/bin/github-merge.py
+chmod +x ~/.local/bin/github-merge.py
+```
+
+- In your Elements repo, configure the merge repository.
+
+```
+git config githubmerge.repository ElementsProject/elements
+```
+
+- Run the script with the PR number you want to test/merge.
+
+```
+github-merge.py <PR_NUMBER>
+```
+
+For example for PR 1518 I see this output:
+
+```
+ElementsProject/elements#1518 Avoid Simplicity header dependency propogation into master
+* 6c7788adf373cd8f0dc5c4fe2b7674625631721e Avoid Simplicity header dependency propogation (Russell O'Connor) (upstream/simplicity, pull/1518/head)
+
+Dropping you on a shell so you can try building/testing the merged source.
+Run 'git diff HEAD~' to show the changes being merged.
+Type 'exit' when done.
+```
+
+- Now you can build and test the PR branch, or do whatever review/testing you require.
+
+- Once you are done testing, comment on the PR with your `ACK BRANCH_COMMIT` and/or comments.
+
+Note: this merge script requires one or more ACKs on the top commit of the PR.
+
+- Type `exit` to continue after testing.
+
+```
+exit
+```
+
+In our example this results in the following output:
+
+```
+[pull/1518/local-merge 5e1a950e52] Merge ElementsProject/elements#1518: Avoid Simplicity header dependency propogation
+ Date: Thu Jan 22 14:49:26 2026 +0200
+ElementsProject/elements#1518 Avoid Simplicity header dependency propogation into master
+* 6c7788adf373cd8f0dc5c4fe2b7674625631721e Avoid Simplicity header dependency propogation (Russell O'Connor) (upstream/simplicity, pull/1518/head)
+ACKs:
+* ACK 6c7788a; built and tested locally  (delta1)
+* ACK 6c7788adf373cd8f0dc5c4fe2b7674625631721e; successfully ran local tests (apoelstra)
+Type 's' to sign off on the above merge, or 'x' to reject and exit.
+```
+
+- If all looks good then type `s` and hit enter to sign off on the merge. Otherwise type `x` and hit enter to exit.
+
+Signing off in our example shows this output:
+
+```
+Type 'push' to push the result to git@github.com:ElementsProject/elements, branch master, or 'x' to exit without pushing.
+```
+
+- Type `push` and hit enter to finish the merge.