Changes:
 - added HTML 5 attribute spellcheck= "true" to text_field tag by adding
        spellcheck: true.
 - Did not add this attribute to text_fields for:
    firstname,
    surname,
    principal_investigator_name &
    data_contact.
   (it is irritating for folk to have a spellchecker say your name is incorrectly spelt.)

Fix for issue #2169.

Fix for issue #2088.

Changes:
    - added a Department model whose instances belong to an org and require name.
    - added a DepartmentController and views for create, edit/update and a index view which is a tab
      of 'Organisational Details'.
    - added the optional attribute department_id to User model.
    - added Rspec tests.
    - updated app/controllers/registrations_controller.rb, app/models/org.rb and
      app/models/user.rb to get rid of outstanding Rubocop warnings

    Fix for issue #2088.