Mapknitter is a free and open-source software created and run by Public Lab. It lets people upload their own aerial images, position them in a web interface over some existing map data, share it, and export for print. It includes a bunch of sub-components - which contains a JavaScript UI- but the core application is written in Rails.
My GSoC project was about upgrading Mapknitter project from Rails 3.2 to Rails 6.0. Initially, the project was running on Rails 3.2. So, to get a smoother upgrade, some steps should be taken before.
I knew that this would involve a lot of work and challenges to overcome, but I got the chance to work with