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

git init

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 git@github.com:your_git_account/your_repo.git into memory (Ctrl-c) and in your local application folder type:

git remote add origin    
git@github.com:your_git_account/your_repo.git

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)

Now say:

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/