Deploy keys gives you read access by default to a single repository. Deploy keys can be given write access when created in github.
In CentOS 7.
yum install rh-git29-git -y
Get public key to import to github.
If you dont have a private/public key create one witht he following command
ssh-keygen -t rsa -b 4096 -C "email@example.com"
To test validation
ssh -T firstname.lastname@example.org