Add OSRA Branches

PT Story: https://www.pivotaltracker.com/story/show/77972984

- [x] Added Branch model and seed data
- [x] Added Branch specs and factory
- [x] Added relationship between Sponsor and Branch
@motasem-salem  for the travils file I say drop `bundle exec rake db:seed` and have
```
bundle exec rake db:create:all
bundle exec rake db:schema:load
```