The answer is to issue a GitLab pull request. A developer must log into the GitLab web application and create a merge request, specify the branch they’re working on as the source and the master branch ...

GitLab made collaboration and encouraging contribution a top priority, so they created the GitLab Merge Request to manage code discussions and code reviews prior to the code changes in a given branch ...

GitLab offers similar functionality for version control including branching, pull requests, merging and conflict resolution. GitLab excels when it comes to developer and tester collaboration.