We control the merging of Github by title and branch.
You can control whether to merge for pull request by setting rules from option screen
As an example, you can make the following settings
・If you add "[WIP]" or "[wip]" to the title, you can not merge it into the master branch
・If you do not add a "Release" to the title, you can not merge it into the master branch or staging branch
・You can merge it into the master branch only from release branch