Estou tentando adicionar um nome de usuário ao meu usuário ao criar.

No projeto / registros / novo eu tenho:

<h2>Sign up</h2>

<%= form_for(resource, :as => resource_name, :url => registration_path(resource_name)) do |f| %>
  <%= devise_error_messages! %>
  <p><%= f.label :username %><br />
  <%= f.text_field :username %></p>

  <p><%= f.label :email %><br />
  <%= f.email_field :email %></p>

  <p><%= f.label :password %><br />
  <%= f.password_field :password %></p>

  <p><%= f.label :password_confirmation %><br />
  <%= f.password_field :password_confirmation %></p>

  <p><%= f.submit "Sign up" %></p>
<% end %>

<%= render :partial => "devise/shared/links" %>

O problema é que não háparams[:username] enviado ao controlador e recebo o seguinte erro na visualização:

ActiveRecord::StatementInvalid in Devise::RegistrationsController#create

Mysql::Error: Column 'username' cannot be null:
  INSERT INTO `users` (`email`, `encrypted_password`, `reset_password_token`,
  `reset_password_sent_at`, `remember_created_at`, `sign_in_count`,
  `current_sign_in_at`, `last_sign_in_at`, `current_sign_in_ip`, `last_sign_in_ip`,
  `created_at`, `updated_at`, `username`) VALUES ('[email protected]',
  '$2a$10$bWjAXLY8QGXrXeVrGciv2O6mjRF940lajBEsUOPPtPDhKyj0A/gia', NULL, NULL,
  NULL, 0, NULL, NULL, NULL, NULL, '2011-05-15 16:16:36', '2011-05-15 16:16:36',
  NULL)

Rails.root: C:/Rails/densjove
Application Trace | Framework Trace | Full Trace

Request

Parameters:

{"utf8"=>"✓",
 "authenticity_token"=>"qkQ8L0ZonXYxWQ2f4cfdREZ222oa2zGUb/qll3TRxjQ=",
 "user"=>{"username"=>"hansen",
 "email"=>"[email protected]",
 "password"=>"[FILTERED]",
 "password_confirmation"=>"[FILTERED]"},
 "commit"=>"Sign up"}

Adicionei ousername coloumn ao meu modelo, mas como posso acessar oparams[:username] no meu controlador?