rails devise emailではなくてusernameでログインしたい

#rails devise emailではなくてユーザー名(username)でログインしたい

ex)https://github.com/plataformatec/devise/wiki/How-To:-Allow-users-to-sign-in-using-their-username-or-email-address
http://d.hatena.ne.jp/CortYuming/20120705/p1

すでにrailsでdeviseが動いている状態

####ユーザー名カラムの追加

$rails g migration AddUsernameToUsers username:string
$rake db:migrate

####userモデルの修正

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable,
            :authentication_keys => [:login]

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

    attr_accessor :login
    attr_accessible :login

    def self.find_first_by_auth_conditions(warden_conditions)
        conditions = warden_conditions.dup
        if login = conditions.delete(:login)
            where(conditions).where(["lower(username) = :value OR lower(email) = :value", { :value => login.downcase }]).first
        else
            where(conditions).first
        end
    end
end

####devise の viewを作成

$rails g devise:views

####devise の viewを編集

app/views/session/new.html.erb
$ diff new.html.erb new.html.erb.org
4,5c4,5
<   <div><%= f.label :login %><br />
<   <%= f.text_field :login, :autofocus => true %></div>
---
>   <div><%= f.label :email %><br />
>   <%= f.email_field :email, :autofocus => true %></div>

app/views/devise/registrations
new.html.erb
$ diff new.html.erb new.html.erb.org
6,8d5
<   <div><%= f.label :username %><br />
<   <%= f.text_field :username, :autofocus => true %></div>

edit.html.erb
$ diff edit.html.erb edit.html.erb.org
6,8d5
<   <div><%= f.label :username %><br />
<   <%= f.email_field :username, :autofocus => true %></div>

####確認

$vi application.html.erb
<% if notice %>
      <p class="notice alert"><%= notice %></p>
    <% end %>
    <% if alert %>
      <p class="alert alert-error"><%= alert %></p>
    <% end %>

    <% if user_signed_in?%>
      <p><%= current_user.email %></p>
      <p class="btn"><%= link_to "Sign out", destroy_user_session_path, :method => :delete %></p>
    <% else %>
      <p class="btn"><%= link_to "Sign up", new_user_registration_path %></p>
      <p class="btn"><%= link_to "Sign in", new_user_session_path %></p>
<% end %>

ブラウザで確認
usernameでログインできた。

OK