Changes

Tsk29-47 Adds the user entity with all tests data
Creates an Admin, Author classes which extend from User. They are used
to create different types of users. Adds new users' data to the SQL and
XML files and the author attribute of the Story has been modified, which
is no longer a String. Adds data to the test dataset and adds a new
matcher for the author. The matchers that had the author attribute have
been modified to use the new author matcher as well as the tests.