How to add my current project to an already existing GitHub repository

Open your Terminal, access to this folder and write:

git init
git add .
git commit -m "my commit"
git remote set-url origin [email protected]:username/repo.git
git push origin master

I had more luck with navigating in my terminal to the directory I wanted to add to the repository, then (assuming you're working on a branch called master):

    git init
    git add .
    git commit -m "my commit"
    git remote add origin <remote repository URL>
    git push origin master

Here's a link to an article explaining how to do it in more detail: https://help.github.com/articles/adding-an-existing-project-to-github-using-the-command-line/

Note that you won't be able to run the "git add ." line if the directory in question is open.