To run this example clone the repo
$ git clone https://github.com/alexiamcdonald/PrincessBride.git
Run Bundle
$ bundle
Run a Rails console
$ rails c
Then create a new movie
$ m = Movie.new
Add a plot to the movie
$ m.plot
Now try and save this plot to see the plot twist
$ m.save
You should see the vengeance_observer
being called.
Congrats you can now go squash some bugs.
Have fun!
You can find my slides in the slides folder