Sometimes you need to have different repositories in sync via ssh, so you don't need to enter login and password each time.
To setup multiple directories with different ssh keys you'll need:
1. Create your keys (2 different):
ssh-keygen -t rsa -b 4096 -C "my_work_email@my_company.com"2. Add your public keys in github repositories respectively - GitHubHelpSSHkeys
3. Make your ~/.ssh/config file look similar:
# Personal GitHub account
Host github.com-personal
HostName github.com
User git
AddKeysToAgent yes
UseKeychain yes
IdentityFile ~/.ssh/personal_rsa