Add department model and service.
Add department to includes
Add department spec fixtures.
Add department tests.
Fix bug in NameEntity string validation where it would crash when the method calling names_cannot_contain_invalid_characters didn't have every single property.
Add validations to Department model
Add tests for sub-departments.
Add method for checking if a Department is a sub_department?
Add Department model spec.
Update readme to indicate that Department is now implemented.
Merge pull request #87 from markrickert/department

Fully implemented Department