What is RUR (Rails Undo Redo) RUR (Rails-Undo-Redo) is a rails plugin (and soon a gem as well) to make it so easy to implement multi-level undo redo in your Rails application that you better start thinking of better excuses not to implement Undo/Redo (no, seriously, it is going to be a lot easier). Try the demo! To get a feel on how undo/redo can help make your app a lot more difficult for users t