Gitlab provides a feature called semi-linear history merge requests which only allows fast forward merge. This ensures the target branch is always green.
If you have a mono repo or a repo with lot of committers, merging a reviewed MR into master branch can get tedious. As only one MR can be merged at a time and all the pending MRs will be invalidated after the merge has to be rebased and tested again.
Assistant tries to automate the flow. Once the MR is reviewed, the
Reviewed label should be added by the reviewer. Assistant will
rebase and merge the reviewed MRs one by one.
Note: Gitlab has another feature called Merge Trains which solves the same issue. You should use that if you have enterprise subscription.