README.md: add content

Resolves: #3

README.md

@@ -1 +1,21 @@
-# authorized_signers file for SSH
+# allowed_signers file for SSH/git
+
+Git 2.34 brings support for signing commits with SSH key and having a SSH-compatible
+smartcard, I have to try this. It likely getting more common in the future doesn't
+hurt either and I have [pgp-alt-wot](https://gitea.blesmrt.net/Mikaela/pgp-alt-wot)
+which does about the same for PGP.
+
+## Where to find keys
+
+* GitHub, Giteas and GitLabs expose user public keys when you append a .keys after their profile page
+* Good ideas are made to be copied, so maybe there will be more repositories like this ;)
+
+## Further reading
+
+* [Caleb Hearth: Signing Git Commits with Your SSH Key](https://calebhearth.com/sign-git-with-ssh), [web.archive.org](https://web.archive.org/web/20211117182628/https://calebhearth.com/sign-git-with-ssh), inspired me to try this
+* [GitHub feedback: Allow using SSH keys to sign commits](https://github.com/github/feedback/discussions/7744)
+  * TODO: notify here when it actually works, link to their guide or maybe remove the section?
+* [Merged Gitea PR for add support for ssh commit signing](https://github.com/go-gitea/gitea/pull/17743)
+  * TODO: link to their blog once it's released
+* [Fedora update request for git](https://bugzilla.redhat.com/show_bug.cgi?id=2029604)
+  * TODO: remove this mention when it happens? It does have the test instructions I took