convert a project directory into new github repo

go to project directory and do following -

git init

git add .

create a repo in github

generate and add public ssh key to git user account under Settings -> SSH and GPG keys

if you get the error "Key already used", you might have used the key in some other github repo

Either you can remove it or create a new pair using following command (NOTE: Press ENTER if it asks for any input to choose default options)

ssh-keygen -t rsa -f ~/.ssh/id_rsa.home

copy contents of id_rsa.home.pub to github

Add the private key to ssh-agent

ssh-add ~/.ssh/id_rsa

If you have generated a new pair, you may need to add the private key (Source: Generate and Add new key)

git remote add origin git@github.com:gituser/myrepo.git

to see impact of above command

git remote -v

You must be ready by now to push to remote repo

git push origin master