Style guides

Ruby. Important sections include Source Code Layout and Naming. Use:
- multi-line method chaining style Option A: dot . on the second line
- string literal quoting style Option A: single quoted by default
Rails
Newlines styleguide
Testing
JavaScript styleguide
SCSS styleguide
Shell commands created by GitLab contributors to enhance security
Database Migrations
Markdown
Documentation styleguide
Interface text should be written subjectively instead of objectively. It should be the GitLab core team addressing a person. It should be written in present time and never use past tense (has been/was). For example instead of prohibited this user from being saved due to the following errors: the text should be sorry, we could not create your account because:
Code should be written in US English
Go

This is also the style used by linting tools such as RuboCop and Hound CI.