A good place to keep dev group? Thread

Hi, so I'm quite(very) new to the indie game dev scene but have a good story, a team of 15 college students and a vaguely good idea of what to do for the next two months. What I want to know is where to keep the whole group? Facebook is fine for alerts, but very restricting as far as file sharing/viewing/etc goes. Google group is what I''m using right now and seems like the best option for me. But what I need is a place where I can put up alerts/notices, keep files pertaining to isntructions, etc, have a flexible(tree-like?) option to keep up and share the story as it develops. Also, I'd rather have whatever portal this is give notification via email so people would check(or send texts to phone). So... is there anything like that out there? Or should I stick to google groups? Seeing how loose my current story is, and how many alternates there are for every point in the game it might get confusing on google groups.

(what about github?)

Facebook groups are the best choice, because his social page have the necessary structure that you waiting for
(sorry ma bad english, im brazilian)

I'm using a mix of Github and Google docs/groups right now. Source code and assets are all stored on Github and design docs stored on Google.

I've done quite a lot of team projects in the past due to working at various dev jobs, and that setup is what I prefer by far. That being said I've never tried using Facebook. I don't think I would like it though cuz I'm not a big fan of Facebook, I find it unreliable compared to Google's services.

Trello is also fairly popular and you might like it, I've just never felt like learning it myself