1. You can implement the microservice using either NodeJS or Java Spring. In any case you should follow the standard best practices for the chosen technology.
2. Your microservice should use Bluemix Cloudant DB. You should build the proper schema, following provided swagger specs; provide a way to initialize the DB with sample data; and to use it inside service implementation.
3. Your solution should be deployed to IBM Bluemix using Docker (IBM Bluemix Container Service).