When you set up an integration from TestRail to GitHub or any other tool, you can configure user variables, which will allow each user to enter his/her own credentials into TestRail for use in the integration.
With user variables set up, you each user would enter credentials under
My Settings > Settings and these credentials would be used when hovering over a GitHub ID in TestRail or using the Push dialog to create new issues.
You can review our documentation for these variables here.
If you want to ensure each user is integrated with their own GitHub credentials, you can remove any fallback values for these variables, as the fallback values would otherwise be used for those users who haven’t stored their own login credentials.
I hope this is helpful,