xp_validations_model.rb

  validates :title, :released_on, :duration, presence: true
  validates :description, length: { minimum: 25 } 
  validates :total_gross, numericality: { greater_than_or_equal_to: 0 }
  validates :image_file_name, allow_blank: true, format: {
      with:    /\w+\.(gif|jpg|png)\z/i,
      message: "must reference a GIF, JPG, or PNG image"
  }


  RATINGS = %w(G PG PG-13 R NC-17)

  validates :rating, inclusion: { in: RATINGS }
  
  
  validates :name, presence: true
  
  validates :email, presence: true,
                  format: /\A\S+@\S+\z/,
                  uniqueness: { case_sensitive: false }
                  
  validates :password, length: { minimum: 10, allow_blank: true }
  
  validates_format_of :username,·
                      :with => /\A[A-Za-z\d_]+$\z/,·
                      :message => "can only be alphanumeric with no spaces"