Add Angular.js
Configure Angular and make controllers XHR aware
Add and configure Restangular
Add ui-router
Add some states
Add ngSanitize
Enable Markdown processing on the client
Convert posts#index to Angular
Fix annoying bug in markdown directive

When the content didn't exist yet, marked raises an error when it's passed
nothing at all. This makes sure something is always passed in for parsing.
Angularify most of the posts#show view
Add some padding in the commenting section
Add an index action for comments
Respond with JSON if requested on comments#create
Use slug as ID in Restangular
Angularize the posts#show page with comments