Set up a git account on github.com. Upload your ssh key. To verify this is done click on top right Account Settings, then ssh keys on left. Then proceed to create a repository on Github. Don’t add a README.
On your local machine, go into your application folder. Type
This creates a .git folder inside the application folder.
git commit -m "Initial Commit"
This will come back with nothing added to commit but untracked files present (use “git add” to track). Then type
git add .
This may take some time if the application is large. In the meantime go to github and copy the SSH link firstname.lastname@example.org:your_git_account/your_repo.git into memory (Ctrl-c) and in your local application folder type:
git remote add origin
Now you need to decide. Do you want images to be backed up too? Unless it’s small better not to. In the application folder create a simple text file called .gitignore (note the dot at the beginning) and add a single line to it. That line should say this:
public/images (where public/images would be the path to your images)
git commit -m "Ignored Images"
Now you are ready to push
git push -u origin master
for a lot more assistance see https://help.github.com/articles/