Add sessions controller and make helpers
Complete 8.2.4. Time to move on to 8.2.5
modify gitignore
Finish 8.2.5. Time to move to 8.2.6
Finish section 8.2.6, time for 8.3
Finish 8.3.2, time for 8.3.3
Finish chapter 8 completely. Time for Chapter 9