RoR : Nested forms with devise - ruby-on-rails

Question

I am new to RoR and I thought I could ask you some help. I didn't find the specific answer I am looking for.
I have a problem with a modelisation I want to make using Devise. Devise sets up a Member model, and I want to have a SuperMember model which have more attributes than Member, and some different views.
I want to set up a nested form to create a SuperMember, while automatically creating the Member account in the background.
Member.rb (generated by devise)
class Member < ActiveRecord::Base
devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable
attr_accessible :email, :password, :password_confirmation, :remember_me
end
SuperMember.rb
class Supermember < ActiveRecord::Base
attr_accessible :first_name, :last_name
belongs_to :member, :dependent => :destroy
accepts_nested_attributes_for :member
end
Supermembers.controllers.rb
def new
#supermember = Supermember.new
#supermember.member = Supermember.build
respond_to do |format|
format.html # new.html.erb
format.json { render json: #supermember }
end
end
def create
#supermember = Supermember.new(params[:supermember])
respond_to do |format|
if #supermember.save
format.html { redirect_to #supermember, notice: 'Supermember was successfully created.' }
format.json { render json: #supermember, status: :created, location: #supermember }
else
format.html { render action: "new" }
format.json { render json: #supermember.errors, status: :unprocessable_entity }
end
end
I tried to create a nested form in order to generate both the member and the supermember :
<%= simple_form_for(#supermember) do |f| %>
<%= f.error_notification %>
<div class="form-inputs">
<%= f.input :first_name %>
<%= f.input :last_name %>
</div>
<% # Devise member %>
<%= f.fields_for :member do |m| %>
<div class="form-inputs">
<%= m.input :email, :required => true, :autofocus => true %>
<%= m.input :password, :required => true %>
<%= m.input :password_confirmation, :required => true %>
</div>
<% end %>
<div class="form-actions">
<%= f.button :submit %>
</div>
<% end %>
The problem is that when I submit this form, I get the following error message :
Can't mass-assign protected attributes: member_attributes
Application Trace | Framework Trace | Full Trace
app/controllers/supermembers.rb:44:in `new'
app/controllers/supermembers.rb:44:in `create'
I really don't understand how to fix it. Could you help me on this one?
Thank you very much!

Answer 1

You need to allow Supermember to accept mass assignment of the member attributes
class Supermember < ActiveRecord::Base
attr_accessible :first_name, :last_name, :member_attributes
...
end

Answer 2

If what you're trying to do is add attributes to member, then it is perfectly OK to do so. There's no need to create a supermember for that purpose only (of course, if you have some other agenda then go ahead...).
Device doesn't care if you add attributes to the model, even if it was generated by it.