Tidy up Gemfile
Fetchable interface for repositories
Make ManualRepository.all order manuals

- Add ManualRecord.all_by_updated_at and have the repo use it
Merge pull request #84 from alphagov/fetchable-interface-for-repositories

Fetchable interface for repositories
Merge pull request #82 from alphagov/order-manuals

ManualRecord.all orders response by updated_at
Fix for editing a manual with sections

Previously, editing a manual would cause it to lose the sections that had
already been created as they weren't being saved on a form update.