NewService - its like a constructor returns a pointer to a new [Service] struct, where Service.Store is a db connection so, every method in this interface can access the db connection.

Comment - a representation of the comment ? structure for our Service.

Service - is the struct on which all our logic will be built on top of.

Store interface: its a contract it ensure that whoeve satisfied this interface decalation they will be directly communicating with these decalared func for example: we defince Store struct in Service layer, so whoever had an instance of this Service they will access the interface decalaration func form anywhere.