clarify logs and gitignore and skipping vendor from now on

Former-commit-id: c8b61b58379d768f04e1593c2a77cf429407cf62

monitor/item.go

@@ -51,7 +51,7 @@ func (i *Item) Compare(other queue.Item) int {
 func (i *Item) Interval() time.Duration {
 	t, err := i.getInterval()
 	if err != nil {
-		log.Println(err)
+		log.Println("[Interval]", err)
 		return forever
 	}
 	return t
@@ -81,14 +81,14 @@ func (i *Item) setInterval(t time.Duration) error {
 func (i *Item) Last() time.Time {
 	t, err := i.getLast()
 	if err != nil {
-		log.Println(err)
+		log.Println("[Last]", err)
 	}
 	return t
 }
 
 func (i *Item) Mark() {
 	if err := i.setLast(time.Now()); err != nil {
-		log.Println(err)
+		log.Println("[Mark]", err)
 	}
 }