Fix GitLab permission denied with ssh keys

1. Check if ssh is installed
2. Run ssh-keygen -t rsa -C "email address"
3. Run eval $(ssh-agent -s)
4. Run ssh-add ~/.ssh/'keyname'
5. Run cat ~/.ssh/'keyname'.pub
6. Copy the output to the clipboard
7. Go to Gitlab > Profile > Settings > SSH Keys
8. Add ney key
9. Copy the copied key into the "Key" field and then "Add key"
10. Test connection with ssh -T git@gitlab.com