Launch agent to add ssh keys to the agent on login.

codes.ka.ssh-add-keychain.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>Label</key>
	<string>codes.ka.ssh-add-keychain</string>
	<key>ProgramArguments</key>
	<array>
		<string>/usr/bin/ssh-add</string>
		<string>--apple-load-keychain</string>
	</array>
	<key>RunAtLoad</key>
	<true/>
</dict>
</plist>

Move into ~/Library/LaunchAgents to load on login.

---

This adds all key's to the ssh-agent. Note that the ssh command already does that when AddKeysToAgent yes is set, but other commands, such as git commit -S, do not. So after a reboot, when you git commit -S before using ssh for the first time, it will not work and instead fail with error: Load key "/var/folders/[...]/.git_signing_key_tmp[...]": invalid format?. This launch agent fixes that.