feat: implement upvote and downvote

interfaces/vote.go

@@ -9,4 +9,6 @@ type NodeVotes interface {
 	msgpack.CustomDecoder
 	Good() int
 	Bad() int
+	Upvote()
+	Downvote()
 }

service/vote.go

@@ -55,3 +55,11 @@ func (n *NodeVotesImpl) DecodeMsgpack(dec *msgpack.Decoder) error {
 
 	return nil
 }
+
+func (n *NodeVotesImpl) Upvote() {
+	n.good++
+}
+
+func (n *NodeVotesImpl) Downvote() {
+	n.bad++
+}