refactor: remove db package and move database logic to service layer

models/node.go

@@ -13,18 +13,6 @@ type Node struct {
 	Relations map[string][]string `json:"relations,omitempty"`
 }
 
-type RelType string
-
-const (
-	RelBlocks      RelType = "blocks"
-	RelSubtask     RelType = "subtask"
-	RelRelated     RelType = "related"
-	RelCreated     RelType = "created"
-	RelAssignee    RelType = "assignee"
-	RelInNamespace RelType = "in_namespace"
-	RelMentions    RelType = "mentions"
-)
-
 func (n *Node) GetProperty(k string) string {
 	for _, t := range n.Tags {
 		if strings.HasPrefix(t, "_") {