Update a destination II

Nicely done! You can now update a destination's name and description. How does it work?

When you visit http://localhost:8000/destinations/1/edit to edit a destination, it triggers the first turn of the request/response cycle:

1. The browser makes a HTTP GET request for the URL /destinations/1/edit.
2. The Rails router maps this URL to the Destinations controller's edit action. The edit action finds the destination with id 1, stores it in @destination, and passes it on to the view app/views/destinations/edit.html.erb.
3. In the view, form_for creates a form with the fields of the @destinations object.

Then when you fill out the form and submit it, it triggers the second turn of the request/response cycle:

1. The browser sends the data to the Rails app via an HTTP POST request to the URL /destinations/update.
2. This time, the Rails router maps this URL to the update action.
3. The update uses the destination_params method to safely collect data from the form. It finds the destination in the database, updates its attributes, and redirects to the destination's show page.