Update README.md
Update README.md
Revised maps
Merge branch 'forstudentviewing' of https://github.com/TeachingDataScience/data-science-course into forstudentviewing
Adding Maps README with background
Update README.md
Update README.md
Update README.md
Update README.md
Update README.md
adding review materials
Merge branch 'forstudentviewing' of github.com:TeachingDataScience/data-science-course into homework