How much does it cost to hire some devs to finish my job?

I have this bathroom project and I need 2-3 plumbers to finish it. How much does that cost?

Funny comment aside, you need to write specifications, talk to Ruby-on-Rails engineers (or an agency) in person to get a proper quote. Don't be surprised if an agency already charges for the first meeting. Alternatively post it on odesk or freelancer.com.

Pay someone to review it. It's by far the best solutions and only real way to get an accurate estimate. I have seen project quoted off the cuff finish at 5 times the original price.

Pay someone.

You're probably won't be out of the woods for under $60k.