First commit on login-logout-branch.  NOTE: naming everything 'login' and 'logout' NOT 'signin/signout'.  Generate Sessions Controller.  Generate rspec integration_test called authentication_pages.  In authentication_pages_spec.rb, created first two Failing tests.
In _header.html.erb partial, renamed 'Sign in' link to 'Login'.
created Sessions resource, restricted to only 'new' 'create' & 'destroy'.  Renamed 'new' to '/login' and 'destroy' to '/logout'.
Create Sessions controller with 'new' 'create' 'destroy' actions.  Create new.html.erb template with correct :title and <h1>. 2 rspec tests pass.
6 Login tests (for Invalid and Valid information). Create 2 login tests, that test for INvalid data submission, tests Fail.  Create 4 more login tests, that test for Valid data submission (which means we are testing for the presence of the user's profile page, and link changes), 4 tests  Fail.
Create login form for new.html.erb.  Once submitted (ie, goes to 'create' action) rerenders to 'new' action (this is temp behavior, later will only do so if INvalid data entered.
Full 'create' action written (dependant on 'login' method).  Then 'login' method NEEDS TO BE created, not yet written.  'login' method will need to be available in controller and view (breaking MVC).  In preperation, we 'include' SessionsHelper, so that 'login' can be made available in the controller (along with the default behavior where helpers are available in the view).
Did a db migrate to add column for remember_token.  Indexed this column, because we will search for users by their remember_token.
Added callback 'before_create :create_remember_token' to User model (as well as appropriate definitions) so that a 'remember_token' is saved when new user is created via signup.
Login working.  CSS changes upon login.  First logout test written.
Login working.  CSS changes upon login.  First logout test written.
session_controller's 'destroy' action defers to logout function.
Logout complete. Finish logout.