Unit test Model/Office.php

[vasildakov]

1. Create a feature branch from develop using github. In order to do that, go to Issues and create the feature branch from the Development section on the right side. Add feature to the name, like feature/example-feature-branch.
2. Create a php unit test for Model/Office with basic test asserting that the object can be created.
3. When finish, create pull request and assign @vasildakov as code reviewer.