Programming :: Rails: No Path For Link_to

I'm still going through "Agile Web Development with Rails" (Beta version), and I'm confused as to why some code in the book is not working for me. Following their example code in the book, I created code like so:

Code:

$ rails demo
# ...
$ cd demo/
$ script/generate controller Say index hello goodbye
exists app/controllers/

[code]...

After starting the server, I can view the index view and the other views just fine. But then I have trouble if I add this code to any of the view html templates:

Code:

<p><%= link_to "Hello", say_hello_path %></p>

I'm told this is supposed to generate a link to the say/hello view. But instead I get an error message like so:

Code:

undefined local variable or method `say_hello_path' for #<ActionView::Base:0xb6ce3090>
If I edit it to

Code:

<p><%= link_to "Hello", Say_hello_path %></p>

then I get

Code:

uninitialized constant ActionView::Base::CompiledTemplates::Say_hello_path

But I haven't noticed anything in the book so far indicating that I am supposed to initialize these constants or how I am supposed to do it.