エラー内容
$ git push origin master
Permission denied (publickey). fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists.
解決策
vagrant 環境でgitの秘密鍵が設定されていないから。
まず、ローカルで
cd .ssh
cp id_rsa ~/Document/work/vagrant
仮想環境で
mv id_rsa ~/.ssh
これでOK!