Instanciate common attributes everywhere so one can simply use the extend method

entry.go

@@ -59,9 +59,10 @@ func (e *Entry) checkAuthors(authorInFeed bool) error {
 // NewEntry creates a new Entry. It returns a *Entry.
 func NewEntry(title string) *Entry {
 	return &Entry{
-		ID:      NewID(NewURN()),
-		Title:   NewText("text", title),
-		Updated: NewDate(time.Now()),
+		CommonAttributes: newCommonAttributes(),
+		ID:               NewID(NewURN()),
+		Title:            NewText("text", title),
+		Updated:          NewDate(time.Now()),
 	}
 }