Remove useless field

	modified:   src/taskboard/data/User.java
	modified:   src/taskboard/data/UserInteractor.java
	modified:   src/taskboard/factory/InMemoryUserInteractor.java
	modified:   src/taskboard/response/UserResponse.java
	modified:   src/taskboard/web/UserGateway.java
	modified:   src/taskboard/web/form/GetUserForm.java
	modified:   src/taskboard/web/form/parser/UserParser.java
	modified:   test/taskboard/AddNewTaskTest.java
	modified:   test/taskboard/data/InMemoryUserInteractorTest.java

	web.xml