username-concept.rb

# app / controllers / application_controller.rb
class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception
  before_filter :configure_permitted_parameters, if: :devise_controller?

  protected

    def configure_permitted_parameters
      devise_parameter_sanitizer.for(:sign_up) { |u| u.permit(:username, :email, :password, :password_confirmation) }
      devise_parameter_sanitizer.for(:sign_in) { |u| u.permit(:username, :email, :password, :remember_me) }
    end
end


# app / models / user.rb
class User < ActiveRecord::Base
  rolify
  include Authority::UserAbilities
    has_many :posts, foreign_key: :id
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable,
  # :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable, :authentication_keys => [:username]
  after_save { self.add_role(:standard) unless self.has_any_role? }
         
  validates_uniqueness_of :username
  validates_presence_of :username
  validates_presence_of :email
  
  def self.find_first_by_auth_conditions(warden_conditions)
    conditions = warden_conditions.dup
    if login = conditions.delete(:username)
      where(conditions).where(["lower(username) = :value OR lower(email) = :value", { :value => login.downcase }]).first
      else
        where(conditions).first
      end
  end
      
end


# config / initializers / devise.rb
config.authentication_keys = [ :login ]