text: var dbm = global.dbm || require('db-migrate');
  var type = dbm.dataType;
  
  exports.up = function (db, callback) {
    db.addColumn('participants', 'discount', {type: 'string'}, callback);
  };
  
  exports.down = function (db, callback) {
    db.removeColumn('participants', 'discount', callback);
  };
  