We need to implement the Groups API in the business logic layer.
- CRUD for Groups
- POST/DELETE/GET for GroupFundFY
NOTE: GET /finance/groups/<id>/budgets may not be needed and is therefore outside the scope of this story. If needed it will be covered in a separate story.
- API is defined and implemented as described on the wiki
- RAML and Module descriptors are updated
- unit tests are updated
- api tests are updated