title: How to set up github readonly access
body: <p>I have a private repo at github and the access is controlled by deployment ssh key pairs. Now I want to set up a read-only access for CI. </p>
  
  <p>I searched this: 
      <a href="https://stackoverflow.com/questions/2868432/github-readonly-access-to-a-private-repo">Github: readonly access to a private repo</a></p>
  
  <p>but still clueless. </p>
  
  <p>Anybody can let me know how to do it? </p>
  
  <p>Thanks in advance!</p>