gluster-web-interface/app/models/user.rb

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable
end

class User::ParameterSanitizer < Devise::ParameterSanitizer
  def initialize(*)
    super
    permit(:sign_up, keys: [:username, :email])
  end
end