Add annotate gem and annotate the models with schema information
Start multisite admin

- Update gitignore for pow
- Update annotation with schema version and indexes
Rename Settings to Site
Add subdomain column to sites and update model. Add subdomain edit field
to the admin.
Basic site creation and routing functionality
Enable cross subdomain session sharing
Add non null site_id column to Campaign, Faq, Payment, Reward and corresponding migrations
Add current site_id default scoping to all necessary models