Ghost/core/server/data/migration/005/04-add-social-media-columns-to-users.js

var Promise = require('bluebird'),
    commands = require('../../schema').commands,
    table = 'users',
    columns = ['facebook', 'twitter'];

module.exports = function addSocialMediaColumnsToUsers(options, logger) {
    var transaction = options.transacting;

    return transaction.schema.hasTable(table)
        .then(function (exists) {
            if (!exists) {
                return Promise.reject(new Error('Table does not exist!'));
            }

            return Promise.mapSeries(columns, function (column) {
                var message = 'Adding column: ' + table + '.' + column;

                return transaction.schema.hasColumn(table, column).then(function (exists) {
                    if (!exists) {
                        logger.info(message);
                        return commands.addColumn(table, column, transaction);
                    } else {
                        logger.warn(message);
                    }
                });
            });
        });
};