Fall is here! Change is in the air. And as of last month, Kickstarter runs its two biggest applications on Rails 5: our payments app, Rosie, and our main app, Kickstarter. In this post, we’ll concentrate on the Kickstarter Rails 5 upgrade. We update our apps because we want to ensure the security and performance of our site — but getting to the next major Rails version on a nine-year-old legacy ap