client side, ssh-key & config
site-a = default: id-rsa
site-b = specific-key: site-b-rsa
Host ghe.hoge.fuga
User git
HostName ghe.hoge.fuga
Port 22
IdentityFile ~/.ssh/site-b-rsa
server side, ssh-pubkey
Add ssh key site-b-rsa.pub
commit author & email
site-a = default: ~/.gitconfig
site-b = specific repositry: git config each repos
git config user.name "hoge.hoge"
git config user.email "hoge@example.com"