Make form for signin
Add authentication to sign-in
  -Finish section 8.1.4, go to 8.1.5
Add functionality for failed signin
  -And make test
  -Go to section 8.2 now
Make skeleton for valid sign in
  -Go to 8.2.1 now
Make remember_token for user to keep user logged in throughout a session
Create sign in for valid user
  -Remember cookies
  -Make layout
  -Make tests
  -Include bootstrap javascript
Sign in user upon successful signup
  -Finish section 8.2.5, go to 8.2.6
Add signout functionality
  -Go to Section 8.3 now