openproject

OpenProject is the leading open source project management software for product, project and portfolio management. A powerful Jira alternative with agile planning, issue tracking, roadmaps, Gantt charts, time tracking, collaboration features, and more. Available on premises or in the cloud. ⭐Star us on GitHub. Maintained by opf on GitHub, where it has earned 15,760 stars from the community.

It's actively developed around project-management, openproject, ruby, and is a solid reference for anyone building with these tools.