So, you want to do some contribution for iPeer project. Just follow the following steps to make your own local development environment.

1. Get a !GitHub Account from https://github.com. 
2. Install Git on your local computer.
 * Mac: http://help.github.com/mac-set-up-git/
 * Linux: http://help.github.com/linux-set-up-git/
 * Windows: http://help.github.com/win-set-up-git/
3. Fork the iPeer project (https://github.com/ubc/iPeer) into your account and  clone the code from your forked repo: http://help.github.com/fork-a-repo/ 
4. Additional steps to set up
 * Pull the Guard plugin.
{{{
cd ipeer
git submodule init
git submodule update
}}}
 * Ignore the updates in config/database.php
{{{
git update-index --assume-unchanged config/database.php
}}}
5. Starting developing~
6. Once you finished, you can issue a pull request so that we can merge your changes to the iPeer repo. http://help.github.com/send-pull-requests/

See, that's not very hard.