Merge branch 'tag-frequency-task' into 'master'

app/controllers/concerns/paginator.rb

app/controllers/v1/search_controller.rb

app/services/tag_search_service.rb

config/routes.rb

lib/tasks/learning_objects_tags.txt

lib/tasks/tag_clustering.rake

lib/tasks/tag_search_aquecimento_global.txt

lib/tasks/tag_search_corrosao.txt

lib/tasks/tag_search_dna.txt

lib/tasks/tag_search_forca_gravitacional.txt

lib/tasks/tag_search_sagitario.txt

lib/tasks/tags.ftree

lib/tasks/tags.net