https://confluence.atlassian.com/bitbucket/configure-multiple-ssh-identities-for-gitbash-mac-osx-linux-271943168.html
1: 生成多个 SSH key
2: 生成config文件来配置对应的key
多个SSH key对应多个Host: Github, Bitbucket
原文：http://www.cnblogs.com/willbin/p/5980027.html
