Added some extra stylings for the gravatar

Added an option argument to the gravatar_for helper, so size can be set across different parts of the site

Added test to ensure errors were being displayed after invalid new user form entry
Changed Flash message html to content_tag. Not sure if this is a real improvement or if it's just the "RAILS WAY"

Tried to make a legit test for the flash message. Could detect the success tag but something wasn't quite there with being able to find the user that was just created.
Added sessions controller and spec
Added first sessions integration tests and configured routes to have a sessions resource
Writing out specs for signin
Added 'new' view for sessions controller

Added sessions spec to handle invalid and valid form entries

Fixed up one of the signup specs, due to mispelling of fake email address
Fixed signin link in the header, to make it legit. Made the sessions 'create' action render the 'new' template.
Added an extra test to ensure Flash message was not persisting beyond it's use. Used Flash.now to sort that out.
Required bootstrap in the JS, woo
included the SessionsHelper, so the controllers also have access to the joys of the current_user, etc
Added sign_in user method to 'create' action, so that sessions generate cookies and are permanent (ie, they actually work!)
Added remember_token and related methods to the User model
Built in a lot of extra navigation into the header partial
Added test for remember_token, woo
Created SessionHelper module, in order to have critical session methods available to both the view and controller.

Chucked a remember_token field into the User table in the DB, so that the backend can figure out if there is a legit user based on their cookie.
Hunted for a typo (turned out to be an unnecessary '@' symbol) that was wrecking sessions

Gutted some other typos as well (and added some unnecessary code to the app controller)
Cut out some unnecessary code
Sorted out the sign-out feature.
Merge pull request #9 from thomasgwatson/chap8

Chap8