Week 1:
	Admin adds a book
	User searches for books
	
Admin adds a book
	check that admin is not logged in
	Admin logs in (by providing a password; no user name necessary)
	check that admin is logged in
	Admin selects add a book
	Admin fills in: Title, Author
	check that the book with the title and author is added

Alternative scenarios
	check that admin is not logged in
	Admin logs in with wrong password
	check that admin is not logged in
	Admin adds a book returns an exception: Admin not logged in (only for the application layer but not for the UI layer)

User searches for books (check for one book, several books, no books)
	User selects "search for books"
	User inputs keyword to search for
	System returns a collection with books that contain the keyword either in the title or in author field

