Better way to share projects?

I am a programmer in Backbone games and we are stressing to release our update on Humanity Falling ( http://humanityfalling.weebly.com ). It just takes too long to share our project to each developer. For example when a programmer edits the project and gives it to me by uploading it on mega. Then I have to download it and add my scripts into it and upload it back on mega so he can download it. At the beginning this was fine, but now it takes 3 hours.

Now I'm asking the Community is there a better way of doing this. Maybe a way to sync the project. I really don't know how other developers can do this. I would appreciate some different alternatives. Thank you for reading.