Connect an issue with a commit after the commit
In your issue on GitHub, just write a comment with the commit hash. For instance:
Fixed with commit 61d949320fc0bf1a8dba09b3845bddcd153b1a64
GitHub will recognize it as a SHA and link to the right commit page.
The Github help page "Can I delete a commit message?" explain how to alter:
- a commit you just pushed
- older commits message
But since it changes the history, you need to make anyone having already pulled from the GitHub repo aware of that change.
If rewriting the history isn't possible, you can make a new commit, with a commit message including:
- the close issue
- the SHA1 of the previous commit.
GitHub will automatically link that old commit in your new commit message: see for istance the reference to commit cdfd948 in this git commit.