implemented joining of times

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

@@ -68,10 +68,20 @@ public class Time implements Mappable{
 		return description;
 	}
 
+	public Time description(String newVal) {
+		description = newVal;
+		return this;
+	}
+
 	public Long end(){
 		return end;
 	}
 
+	public Time end(Long newVal) {
+		end = newVal;
+		return this;
+	}
+
 	public long id(){
 		return id;
 	}
@@ -143,6 +153,11 @@ public class Time implements Mappable{
 		return subject;
 	}
 
+	public Time subject(String newValue) {
+		subject = newValue;
+		return this;
+	}
+
 	public Collection<Long> taskIds(){
 		return taskIds;
 	}