class Venue < ActiveRecord::Base attr_accessible :name, :description, :website, :address, :photo has_many :conferences before_create :generate_guid has_attached_file :photo, styles: { thumb: '100x100>', large: '300x300>' } validates_attachment_content_type :photo, content_type: [/jpg/, /jpeg/, /png/, /gif/], size: { in: 0..500.kilobytes } private def generate_guid begin guid = SecureRandom.urlsafe_base64 end while Venue.where(:guid => guid).exists? self.guid = guid end end