wrangling that flow control tho

db.js

db.postClassified = function(data, callback) {
    var tx = new Transaction(client);
    async.waterfall([
        function(cb) { tx.begin(cb); },
        function(result, cb) {
            if (!data.image_name) return cb(null, null);
            tx.query("INSERT INTO images (file_name) VALUES ($1) RETURNING id", [data.image_name], cb);
        },
        function(result, cb) {
            tx.query("INSERT INTO classifieds (email, phone_number, name, posting_title, price, address, image, posting_body, condition) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)",
                    [data.email, data.phone_number, data.name, data.posting_title, data.price, data.address, result ? result.rows[0].id : null, data.posting_body, data.condition], cb);
        },
        function(result, cb) { tx.commit(callback); }
    ], callback);
};