adding other exercises up to ex9
adding other exercises up to ex9
Exercise 12.
Merge pull request #3 from luiswe7/master

Exercise 12.
Merge branch 'master' of https://github.com/grahaminn/learning-sql-the-hard-way
Merge pull request #2 from AndyBarnett/master

ex11 from AB
Merge branch 'master' of https://github.com/grahaminn/learning-sql-the-hard-way
count how many subscribers streamed last week