now inheriting due date when child task is created

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

core/src/main/java/de/srsoftware/umbrella/core/model/Task.java

@@ -65,6 +65,11 @@ public class Task implements Mappable {
 		return this;
 	}
 
+	public Task dueDate(LocalDate newValue) {
+		dueDate = newValue;
+		return this;
+	}
+
 	public LocalDate dueDate(){
 		return dueDate;
 	}