#  id         :integer(4)      not null, primary key
#  category   :string(255)
#  content    :text
class Question < ActiveRecord::Base
    has_many :choices, :dependent => :destroy
    accepts_nested_attributes_for :choices
end

#  id          :integer(4)      not null, primary key
#  content     :text
#  correct     :boolean(1)
#  question_id :integer(4)
class Choice < ActiveRecord::Base
    belongs_to :question
end

def new
    @title = "New Question"
    @question = Question.new
    3.times { @question.choices.build }

    respond_to do |format|
        format.html # new.html.erb
        format.xml  { render :xml => @question }
    end
end

<%= simple_form_for @question do |question_form| %>
    <%= question_form.error_notification %>

    <div class="inputs">
    <%= question_form.input :content, :label => 'Question' %>
    <%= question_form.input :category, :collection => get_categories, :include_blank => false %>

    <% @question.choices.each do |choice| %>
        <%= question_form.fields_for :choices, choice do |choice_fields| %>
            <%= choice_fields.input :content, :label => 'Choice' %>
            <%= choice_fields.radio_button :correct, true %>
            <%= choice_fields.label :correct, 'Correct Answer' %>
        <% end %>
    <% end %>
    </div>

    <div class="actions">
    <%= question_form.button :submit %>
    </div>
<% end %>

def create
    @question = Question.new(params[:question])
    # render or redirect stuff....
end

<%= choice_fields.radio_button :correct, true, :name => "choices_attributes" %>

<%= choice_fields.radio_button :correct, true %>
<%= choice_fields.label :correct, value: true, do %>
  'True'
<% end %>
<%= choice_fields.radio_button :correct, false %>
<%= choice_fields.radio_button :correct, value: false, do %>
  'False'
<% end %>