Add some documentation to the API
Based on https://github.com/gin-gonic/gin/issues/155, it could be cool to publish some API documentation.
Ref: https://github.com/swaggo/gin-swagger https://github.com/swaggo/swag https://github.com/savaki/swag https://github.com/savaki/swag/blob/master/examples/gin/main.go https://github.com/go-swagger/go-swagger