Introduced interfaces for all repositories, completely isolating the persistence layer from the repositories usage and specification

persistence/album_repository.go

@@ -4,24 +4,24 @@ import (
 	"github.com/deluan/gosonic/domain"
 )
 
-type Album struct {
-	BaseRepository
+type albumRepository struct {
+	baseRepository
 }
 
-func NewAlbumRepository() *Album {
-	r := &Album{}
+func NewAlbumRepository() domain.AlbumRepository {
+	r := &albumRepository{}
 	r.init("album", &domain.Album{})
 	return r
 }
 
-func (r *Album) Put(m *domain.Album) error {
+func (r *albumRepository) Put(m *domain.Album) error {
 	if m.Id == "" {
 		m.Id = r.NewId(m.ArtistId, m.Name)
 	}
 	return r.saveOrUpdate(m.Id, m)
 }
 
-func (r *Album) Get(id string) (*domain.Album, error) {
+func (r *albumRepository) Get(id string) (*domain.Album, error) {
 	var rec interface{}
 	rec, err := r.readEntity(id)
 	return rec.(*domain.Album), err