Updated Readme - readme-edits

Pull requests let you tell others about changes you've pushed to a GitHub repository. Once a pull request is sent, interested parties can review the set of changes, discuss potential modifications, and even push follow-up commits if necessary.

Pull Requests are the heart of collaboration on GitHub. When you make a pull request, you’re proposing your changes and requesting that someone pull in your contribution - aka merge them into their branch. GitHub’s Pull Request feature allows you to compare the content on two branches. The changes, additions and subtractions, are shown in green and red and called diffs (differences).

As soon as you make a change, you can open a Pull Request. People use Pull Requests to start a discussion about commits (code review) even before the code is finished. This way you can get feedback as you go or help when you’re stuck.