add models and migrations

app/models/ability.rb

app/models/communication/extranet.rb

app/models/university/organization/category.rb

app/models/university/person/category.rb

...ate/20230313114113_create_university_person_categories.rb

...230313114528_create_university_organization_categories.rb

db/schema.rb

test/fixtures/communication/extranets.yml

test/fixtures/university/organization/categories.yml

test/fixtures/university/person/categories.yml

test/models/communication/extranet_test.rb

test/models/university/organization/category_test.rb

test/models/university/person/category_test.rb