refactor: introduce store.Store graph interface with SQLite implementation

service/node_service.go

@@ -1,6 +1,9 @@
 package service
 
-import "axolotl/models"
+import (
+	"axolotl/models"
+	"axolotl/store"
+)
 
 type NodeService interface {
 	Create(title, content, dueDate string, tags []string, rels map[models.RelType][]string) (*models.Node, error)
@@ -13,15 +16,15 @@ type NodeService interface {
 }
 
 func InitNodeService(path string) error {
-	return InitSqliteDB(path)
+	return store.InitSQLiteStore(path)
 }
 
 func GetNodeService(cfg Config) (NodeService, error) {
-	db, err := GetSqliteDB(cfg)
+	st, err := store.FindAndOpenSQLiteStore()
 	if err != nil {
 		return nil, err
 	}
-	return &sqliteNodeService{db: db, userID: cfg.GetUser()}, nil
+	return &nodeServiceImpl{store: st, userID: cfg.GetUser()}, nil
 }
 
 type listFilter struct {