Can't create User, getting "ActiveRecord::RecordInvalid: Validation failed: Password can't be blank" Error

Question

I have some serious problem with understanding what is wrong in my code after implemented "has_secure_password" . My issue to use "has_secure_password" and create new User.

I am using rails 4

Gemfile

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.5'
gem 'mysql2', '>= 0.3.13', '< 0.5'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.1.0'
gem 'jquery-rails'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'sdoc', '~> 0.4.0', group: :doc
gem 'bcrypt', '~> 3.1.7'

2.2.3 :034 > user=User.new(name: "user2", email: "user2@mail.com", password: "1qaz!QAZ", password_confirmation: "1qaz!QAZ") => # 2.2.3 :035 > user.save! (0.4ms) BEGIN User Exists (0.3ms) SELECT 1 AS one FROM users WHERE users.email = 'user2@mail.com' LIMIT 1 (0.1ms) ROLLBACK ActiveRecord::RecordInvalid: Validation failed: Password can't be blank

My User model

class User < ActiveRecord::Base

  attr_accessor :password, :password_confirmation, :remember_token
  has_secure_password

  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
  validates :email, presence:   true,
    format:     { with: VALID_EMAIL_REGEX },
    uniqueness: { case_sensitive: false }
  before_save { email.downcase! }

  validates :password, length: { minimum: 6 }

end

please help me to understand what is wrong in my code.