設計未定義的方法`電子郵件」

每當我打出了牌子的按鈕，我得到以下錯誤：設計未定義的方法`電子郵件」

NoMethodError in Devise/sessions#new 

Showing /Users/chanel.n/svn- work/gwb/trunk/PMOCCU/ProcessEnforcer/app/views/devise/sessions/new.html.erb where line #5 raised: 

undefined method `email' for #<User id: nil, name: nil, created_at: nil, updated_at: nil> 
Extracted source (around line #5): 

2: 
3: <%= form_for(resource, :as => resource_name, :url => session_path(resource_name)) do |f| %> 
4: <div class="field"><%= f.label :email %><br /> 
5: <%= f.email_field :email %></div> 
6: 
7: <div class="field"><%= f.label :password %><br /> 
8: <%= f.password_field :password %></div> 
Rails.root: /Users/chanel.n/svn-work/gwb/trunk/PMOCCU/ProcessEnforcer 

Application Trace | Framework Trace | Full Trace 
app/views/devise/sessions/new.html.erb:5:in `block in _app_views_devise_sessions_new_html_erb___4179931318693150703_70215900182100' 
app/views/devise/sessions/new.html.erb:3:in `_app_views_devise_sessions_new_html_erb___4179931318693150703_70215900182100'

這裏是我的用戶模型，其中包括電子郵件：

class User < Role 
has_and_belongs_to_many :roles 

attr_accessible :name, :roles 

# Include default devise modules. Others available are: 
# :token_authenticatable, :confirmable, 
# :lockable, :timeoutable and :omniauthable 
devise :database_authenticatable, :registerable, 
    :lockable, :timeoutable, :trackable, :validatable, :token_authenticatable 

# Setup accessible (or protected) attributes for your model 
attr_protected :email, :password, :password_confirmation, :department, :encrypted_password 
# attr_accessible :title, :body, :remember_me 

validates_presence_of :email 

end

無論出於何種原因，它不承認電子郵件。

有沒有其他人遇到過這個問題？

來源

2012-07-26 Chanel Nalani