Ask HN: An Online Spreadsheet Certain People can Edit

So my wife is coaching a team, and she wants a way for the parents to all post their contact information somewhere online where only her and other parents of the team can see it.

What's the best method to accomplish this?

(I thought a google spreadsheet might work, but not everyone has a gmail account, and if I make it public I wouldn't want to take the chance of exposing everyone's contact info to the internet.)