Add Mikołaj Wawrzyniak as BE maintainer (Gitlab)

Trainee maintainer issue: #7777 (closed)

Overview

I've 13 months experience as backend developer at Gitab. I've worked at two teams: groupapm and ~"product analytics(telemetry)" so far, during that time I have:

• got 69 MRs merged to gitlab-org/gitlab project and 83 MRs in total
• reviewed over 88 sucessfully merged MRs
• spent 5 months on trainee programme, and has record of over 50 MRs reviewed at the time #7777 (closed)
• spot and lead discussion around significant architectural change gitlab-org/gitlab#219639 (comment 354570000) and https://www.youtube.com/watch?v=9IXVDFh-rLQ&feature=youtu.be (private video on GitLab Unfiltered channel)

Examples of reviews

• gitlab-org/gitlab!34503 (merged) (although it was backend review, MR was focused on modifying database querying logic, in MR I paid attention to both aspects and suggested different approaches that were promising good perfromance)
• gitlab-org/gitlab!44023 (merged) (I've analyzed not only MR changes but context for them, and suggested how to reuse existing code, rather than adding redundant methods)
• gitlab-org/gitlab!34644 (merged) (I've suggested how to improve code architecture, to avoid duplication of hardcoded parameters, and make it better aligned with OO good practices)

My trainee #7777 (closed) issue contains exhaustive list of reviews I've performed

Things to improve

• Self - confidence to keep up quality bar during prolonging review (#7777 (comment 401646860)) Sometimes I struggle to keep asking or improvements, when I know that I've already had a lot of remarks, and remaining things are not critical and shouldn't lead to regression.
• Keep on learning on different aspects of gitlab and Rails framework eg: Difference between ProcessMemoryCache and Rails.cache (#7777 (comment 431677640))

@gitlab-org/maintainers/rails-backend please chime in below with your thoughts, and approve this MR if you agree.

Developer checklist

• Before this MR is merged
  • Mention @gitlab-org/maintainers/rails-backend, if not done (this issue template should do this automatically)
  • Assign this issue to your manager
• After this MR is merged
  • Request a maintainer from the #backend_maintainers Slack channel to add you as an Owner to gitlab-org/maintainers/rails-backend
  • Consider adding 'backend maintainer' to your Slack notification keywords

Manager checklist

• Before this MR is merged
  • The MR has been open for 5 working days
  • More than half of the existing maintainers approve the MR
  • There are no blocking concerns raised (if there are, please follow https://about.gitlab.com/handbook/engineering/workflow/code-review/#how-to-become-a-project-maintainer)
• After this MR is merged
  • Announce the good news in the relevant channels listed in https://about.gitlab.com/handbook/engineering/#keeping-yourself-informed