added opt_in into user model
added opt_in into user model

emoncms/emoncms,emoncms/emoncms,chaveiro/emoncms,chaveiro/emoncms,chaveiro/emoncms,emoncms/emoncms,emoncms/emoncms,inverse/emoncms,inverse/emoncms,inverse/emoncms,inverse/emoncms,emoncms/emoncms,chaveiro/emoncms