A typical user model in rails

ruby: user.rb

# Gem 'bcrypt-ruby'
# Generate User model with password_digest field
class User < ActiveRecord::Base
  has_secure_password
  attr_accessible :email, :name, :password, :password_confirmation
  before_save { self.email.downcase! }  
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i  
  validates :email, presence: true, uniqueness: {case_sensitive: false}, 
            length: {maximum: 50}, format: { with: VALID_EMAIL_REGEX }
  validates :name, presence: true,  uniqueness: true
  validates :password, length: {minimum: 5}
end