A fast-growing investing app called Stash is trying to make money by making investing enjoyable again. Its co-founders, Brandon Krieg and Ed Robinson, say they can do that without inspiring their customers to do anything too stupid. Stash is built on the premise that there’s a pool of people, particularly millennials, who want to “believe” in the companies they invest in. CEO David Ronick says the goal is to break down barriers to investment. Stash thinks that some millennials want to take values into consideration in the same way they think about returns.