Nil object for nested resource

Rails
1

Hi all,

I have 2 models with a standard 1 to many relationship. I’m also
using
REST on the two models and have added the appropriate code to the
routes.rb file.

scorecard.rb:

class Scorecard < ActiveRecord::Base
has_many :attributes
end

attribute.rb:

class Attribute < ActiveRecord::Base
belongs_to :scorecard
end

routes.rb:

map.resources :scorecards do |scorecard|
scorecard.resources :attributes
end

My problem is that I want to show a single scorecard with all it’s
attributes. I then want to display a “New attribute” link to add a
new
attribute to the current scorecard.

scorecards/show.rhtml:

<%= label_for(“scorecard”) %>
<%=h @scorecard.name %>

<%= label_for(“template”) %>
<%=h @scorecard.template %>

Attributes:

<% for attribute in @scorecard.attributes %> <% end %>
<%=h attribute.name %> <%=h attribute.weight %>
<%= link_to "New Attribute", new_attribute_path(@scorecard) %>

However I get the message for line 17 (last line) when I try to view
this page,

You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.to_sym

I have tried checking against various REST and Rails books and
articles,
and I thought I had used the correct syntax for creating a link to a
new
attribute from this scorecard.

Any help on this would be greatly appreciated.

Thanks,

Matthew