RFR - Ma edit reviews

To use `form_for` with nested resources, you can pass in the two objects whose IDs you need in the route:

```erb
<%= form_for [@bus, @review] do |f| %>
  # ...
<% end %>
```

(You don't need to specify patch because `form_for` is smart enough to know that when the `@review` object that's passed to it has been persisted to the DB, it should generate a PATCH request.  Otherwise, it'll generate a POST request.)

That said, I probably wouldn't use nested resources here, because you don't need them.  To update a review, you just need that review (whereas to make a review, you'd need the bus -- or ride -- as well).

```ruby
# routes.rb
  resources :buses, only: [:index, :show] do
    resources :reviews, only: [:new, :create, :edit]
  end

  resources :reviews, only: [:update, :destroy]

# edit.html.erb
<%= form_for @review do |f| %>
  # ...
<% end %>
```