Multistep Nested Forms Using Rails
I'm trying to implement a multistep form using a nested form, but since I'm using a nested form, it's not working out like the railscast. I got this from railscast #217 (multistep form/wizards) http://railscasts.com/episodes/217-multistep-forms

### old _event.html.erb form

    <%= render "event_details", :f => f %>

    <%= render "sandwich_details", :f => f %>

### new version of _event.html.erb

    <%= render "#{@event.current_step}_details", :f => f %>

I get a "undefined method `current_step` for nil:NilClass" error. 
I think this is because `event` is nested inside `user`, so I'm not directly 
using a forms_for method like in the railscast. Here's the loop leading up to 
this point. I followed the railscast up to the point where he refreshed the page 
for the first time.

### _forms.html.erb

    <% form_for @user do |f| %> 
    .
    .
    .
       <% f.fields_for :events do |event_form| %>
          <%= render :partial => 'event', :locals => {:f => event_form } %>
       <% end %> 
    <% end %>

### event.rb

    class Event < ActiveRecord::Base
      belongs_to :user
      attr_writer :current_step
    
      def current_step
        @current_step || steps.first
      end
    
      def steps
        %w[event_details item_details]
      end

How can I change `"#{@event.current_step}_details"` to make it find current_step?

Multistep Nested Forms Using Rails
===

I'm trying to implement a multistep form using a nested form, but since I'm using a nested form, it's not working out like the railscast. I got this from railscast #217 (multistep form/wizards) http://railscasts.com/episodes/217-multistep-forms

### old _event.html.erb form

    <%= render "event_details", :f => f %>

    <%= render "sandwich_details", :f => f %>

### new version of _event.html.erb

    <%= render "#{@event.current_step}_details", :f => f %>

I get a "undefined method `current_step` for nil:NilClass" error. 
I think this is because `event` is nested inside `user`, so I'm not directly 
using a forms_for method like in the railscast. Here's the loop leading up to 
this point. I followed the railscast up to the point where he refreshed the page 
for the first time.

### _forms.html.erb

    <% form_for @user do |f| %> 
    .
    .
    .
       <% f.fields_for :events do |event_form| %>
          <%= render :partial => 'event', :locals => {:f => event_form } %>
       <% end %> 
    <% end %>

### event.rb

    class Event < ActiveRecord::Base
      belongs_to :user
      attr_writer :current_step
    
      def current_step
        @current_step || steps.first
      end
    
      def steps
        %w[event_details item_details]
      end

How can I change `"#{@event.current_step}_details"` to make it find current_step?
