Update README.md

poor-man's git usage:
1. create a repository, grab the .git URL
2. "git clone https://github.com/knail1/stocrates.git" to pull into your local computer
3. add new code in the relevant directories
4. after changes, issue "git add <file> "
5. then, do a commit "git commit -a" , add comments
6. then push it back to github: "git push"