implemented various task features:

- saving on CTRL+S
- editing of
    - start date
    - due date
    - members

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

@@ -32,6 +32,16 @@ public class Project implements Mappable {
 		this.members = members;
 	}
 
+	public Project clean() {
+		dirtyFields.clear();
+		return this;
+	}
+
+	public Project clean(String field){
+		dirtyFields.remove(field);
+		return this;
+	}
+
 	public Optional<Long> companyId(){
 		return nullable(companyId);
 	}
@@ -40,8 +50,9 @@ public class Project implements Mappable {
 		return description;
 	}
 
-	public Set<String> dirtyFields(){
-		return dirtyFields;
+	public Project dirty(String field){
+		dirtyFields.add(field);
+		return this;
 	}
 
 	public boolean hasMember(UmbrellaUser user) {
@@ -52,6 +63,15 @@ public class Project implements Mappable {
 		return id;
 	}
 
+	public boolean isDirty() {
+		return !dirtyFields.isEmpty();
+	}
+
+	public boolean isDirty(String field){
+		return dirtyFields.contains(field);
+	}
+
+
 	public Map<Long,Member> members(){
 			return members;
 	}
@@ -103,12 +123,4 @@ public class Project implements Mappable {
 		map.put(MEMBERS,memberMap);
 		return map;
 	}
-
-	public boolean isDirty() {
-		return !dirtyFields.isEmpty();
-	}
-
-	public void clean() {
-		dirtyFields.clear();
-	}
 }

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

@@ -46,14 +46,25 @@ public class Task implements Mappable {
 		this.members = members;
 	}
 
-	public void clean() {
+	public Task clean() {
 		dirtyFields.clear();
+		return this;
+	}
+
+	public Task clean(String field){
+		dirtyFields.remove(field);
+		return this;
 	}
 
 	public String description(){
 		return description;
 	}
 
+	public Task dirty(String field){
+		dirtyFields.add(field);
+		return this;
+	}
+
 	public LocalDate dueDate(){
 		return dueDate;
 	}
@@ -70,6 +81,10 @@ public class Task implements Mappable {
 		return !dirtyFields.isEmpty();
 	}
 
+	public boolean isDirty(String field){
+		return dirtyFields.contains(field);
+	}
+
 	public Map<Long,Member> members(){
 		return members;
 	}
@@ -145,7 +160,7 @@ public class Task implements Mappable {
 				case STATUS:         status        = json.get(key) instanceof Number number ? Status.of(number.intValue()) : Status.valueOf(json.getString(key)); break;
 				default: {
 					key = null;
-					LOG.log(WARNING,"Tried to patch field ''{0}'' of task, which is not implemented!");
+					LOG.log(WARNING,"Tried to patch field ''{0}'' of task, which is not implemented!",key);
 				}
 			}
 			if (key != null) dirtyFields.add(key);