test 'createSessionShouldThrowWhenScrumMasterNameIsEmpty'
added test: createSessionShouldReturnSessionWithGivenScrumMasterName
extracted Session class to dedicate source file
added test SessionController.joinSessionShouldThrowWhenTeamMemberNameIsEmpty
redone Session export
added test SessionController.joinSessionShouldReturnTeamMemberWithGivenName