Merge branch 'feature-tags'

Gemfile

app/controllers/concerns/taggable_controller.rb

app/controllers/v1/collections_controller.rb

app/controllers/v1/learning_objects_controller.rb

app/models/collection.rb

app/models/concerns/taggable.rb

app/models/concerns/tagger.rb

app/models/institution.rb

app/models/learning_object.rb

app/models/tag.rb

app/models/tagging.rb

app/models/user.rb

app/policies/collection_policy.rb

app/policies/learning_object_policy.rb

app/policies/taggable_policy.rb

app/serializers/collection_serializer.rb

app/serializers/learning_object_serializer.rb

app/services/tags_importer.rb

config/routes.rb

...ts_as_taggable_on_migration.acts_as_taggable_on_engine.rb