Adding the original repository as a remote it is important so that you can "fetch" future lab sessions materials.
From the shell command line, enter your repository folder and follow these steps:
git remote add upstream https://github.com/cdparra/introsde2013.git
Now, the following two commands must be executed before each lab session
git fetch upstream
git merge upstream/master
Git merge download new files/changes in the original repo (without modifying your own) git merge apply these changes.