Modifying tasks works

model.go

@@ -48,6 +48,19 @@ func (a *AppState) addTask(taskString string) error {
 	return a.WriteList()
 }
 
+func (a *AppState) saveTask(t *todotxt.Task) error {
+	lt, err := a.TaskList.GetTask(t.Id)
+	if err != nil {
+		return err
+	}
+	lt.Todo = t.Todo
+	lt.Priority = t.Priority
+	lt.Projects = t.Projects
+	lt.Contexts = t.Contexts
+	lt.AdditionalTags = t.AdditionalTags
+	return a.WriteList()
+}
+
 func (a *AppState) toggleTaskComplete(id int) error {
 	if a.diskListChanged() {
 		return a.e(ResStrListChanged)