tags および tag_names にて論理削除を物理削除に変更 (#416) (#418)

Reviewed-on: #418
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/spec/requests/posts_spec.rb

@@ -1252,9 +1252,7 @@ RSpec.describe 'Posts API', type: :request do
 
     context 'when nico tag already exists in tags' do
       before do
-        Tag.find_undiscard_or_create_by!(
-            tag_name: TagName.find_undiscard_or_create_by!(name: 'nico:nico_tag'),
-            category: :nico)
+        Tag.find_or_create_by_tag_name!('nico:nico_tag', category: :nico)
       end
 
       it 'returns 422 with tag field errors' do
@@ -1580,9 +1578,7 @@ RSpec.describe 'Posts API', type: :request do
 
     context 'when nico tag already exists in tags' do
       before do
-        Tag.find_undiscard_or_create_by!(
-            tag_name: TagName.find_undiscard_or_create_by!(name: 'nico:nico_tag'),
-            category: :nico)
+        Tag.find_or_create_by_tag_name!('nico:nico_tag', category: :nico)
       end
 
       it 'returns 422 with tag field errors' do