Step 1.
Fetch and check out the branch for this merge request
git fetch origin
git checkout -b development origin/development
Step 2.
Review the changes locally
Step 3.
Merge the branch and fix any conflicts that come up
git checkout master
git merge --no-ff development
Step 4.
Push the result of the merge to GitLab
git push origin master
Note that pushing to GitLab requires write access to this repository.
