Validate website url

comment.rb

class Comment < ActiveModel::Base
  validate :valid_url?, :allow_blank => true
  def valid_url?
    if (self.website).start_with?("http://", "https://") and (self.website).end_with?(".*")
      return true
    elsif (self.website).end_with?(".*")
      return true
      self.website = "http://#{self.website}"
    else
      return self.errors[:website] << "The website you entered (#{self.website}) is invalid. Please try again."
    end
  end
end