Implement basic CRUD ops for vouchers.
Please create a new interface for vouchers.
See the API listing for endpoint details: https://docs.google.com/spreadsheets/d/1se-a2owRfHLG5eaAZglx4vLvRClCKGp2wZCfD39ZJRY/edit#gid=206331518
Schemas and sample data are outside the scope of this story and will be handled in another story.
- Voucher APIs are implemented
- RAML cop linting passes w/o errors
- Unit tests have been updated