Lessons learned in a major Rails upgrade

This is a 3 part series on lessons learned from our recent Rails upgrade.Lessons on strategyLessons on project managementLessons on toolingAt Invoca, we have recently upgraded our Rails app containing multiple million lines of code from Rails 4 to Rails 5. In this article, we cover some of the tooling that helped us perform the upgrade without wasting too much time.These lessons can be used for any major Rails upgrade. In fact, we expanded on many of the learnings from our previous upgrade.Tooling and documentation saved us a lot of time and made it easy for any developer to contribute to the project.