session.rb

class Session
  include ActiveModel::Model

  attr_accessor :email, :password
  validates :email, :presence => { :message => 'Entre com o seu e-mail' }
  validates :password, :presence => { :message => 'Coloque a sua senha' }

  def initialize(attr={})
    @email = attr[:email]
    @password = attr[:password]
  end

  def authenticate!
    return false if @email.blank? || @password.blank?

    user = User.find_by(email: @email)
    if user && user.authenticate(@password)
      session[:id] = user.id
    else
      errors.add(:invalid, 'Usuário ou senha incorretos')
      false
    end
  end

end