Chapter 3 / 11
Chapter 3 / 12 : Ignore failing test for now.

The test appears not to be fixed right away because
no implementation of actually removing a tweet is
provided. Hence, we ignore the test for now.
Chapter 3 / 12
Chapter 3 / 13
Chapter 3 / 15

Note: 3 / 14 is identical to 3 /13.
Chapter 3 / 16
Chapter 3 / 17
Chapter 3 / 18