# Development - [Architecture](architecture.md) of GitLab - [Shell commands](shell_commands.md) in the GitLab codebase - [Rake tasks](rake_tasks.md) for development - [CI setup](ci_setup.md) for testing GitLab - [Sidekiq debugging](sidekiq_debugging.md) - [UI guide](ui_guide.md) for building GitLab with existing css styles and elements