perf: do a bulk insert in fetchCollection

Improve performance over inserting each item individually

pkg/node.go

@@ -1,6 +1,13 @@
 package synchronizator
 
-type StandardNode interface{}
+type StandardNode interface {
+	GetClass() string
+	GetName() string
+	GetMetadata() []byte
+
+	SetId(int64)
+	SetConnection(*DB)
+}
 
 // A node in the database.
 // It adds some helper methods to easily manage the node.
@@ -13,6 +20,26 @@ type Node struct {
 	metadata       []byte          // Arbitrary data. This is stored as a jsonb in the database
 }
 
+func (node *Node) GetClass() string {
+	return node._class
+}
+
+func (node *Node) GetName() string {
+	return node.name
+}
+
+func (node *Node) GetMetadata() []byte {
+	return node.metadata
+}
+
+func (node *Node) SetId(id int64) {
+	node.Id = id
+}
+
+func (node *Node) SetConnection(conn *DB) {
+	node._conn = conn
+}
+
 // Creates a new relation of type StandardRelationship to the node with the
 // provided id. An error is returned if the relation already exists.
 //