Rubyonrails Rails：try 登录时出现BCrypt：：Errors：：InvalidHash

我正在努力完成一个项目.我正在与用户模型合作.

很抱歉，出了点问题.

BCrypt::Errors::InvalidHash (invalid hash):
  app/controllers/sessions_controller.rb:8:in `create'

我的目标是:

class SessionsController < ApplicationController

  def new
  end

   def create
    user = User.find_by_email(params[:session][:email])
    if user && user.authenticate(params[:session][:password])
      sign_in user
      redirect_to user
    else
      flash.now[:error] = 'Invalid email/password combination'
      render 'new'
    end
  end


  def destroy
    sign_out
    redirect_to root_path
  end
end

user model是:

class User < ActiveRecord::Base
  attr_accessible :email, :name, :nickname,:password, :password_confirmation 
  has_secure_password


  before_save { |user| user.email = email.downcase }
  before_save { |user| user.nickname = nickname.downcase }
  before_save :create_remember_token
....validations......

    private

    def create_remember_token
      self.remember_token = SecureRandom.urlsafe_base64
    end
end 

这是我的session.helper美元

module SessionsHelper

  def sign_in(user)
    cookies.permanent[:remember_token] = user.remember_token
    self.current_user = user
  end
  def signed_in?
    !current_user.nil?
  end

  def current_user=(user)
    @current_user = user
  end

  def current_user
    @current_user ||= User.find_by_remember_token(cookies[:remember_token])
  end

  def sign_out
    self.current_user = nil
    cookies.delete(:remember_token)
  end
end

我试过heroku rake db:迁移，heroku重启..没有变化.