Before working on the project and pushing, you must pull all the new commits. 
Here's how:

  cd ./CSE360-Project
  git fetch upstream
  git merge upstream/master


After Fetching and Merging:

  git add -A
  git commit -m 'Your message here'
  git push origin master

DONE!

To change the remote 'origin':
  git remote set-url origin git@github.com:LearnToPlay/CSE360-Project.git