feat: テスト自動化（#104） (#220)

#104

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #220

backend/Gemfile

@@ -65,3 +65,5 @@ gem 'dotenv-rails'
 gem 'whenever', require: false
 
 gem 'discard'
+
+gem "rspec-rails", "~> 8.0", :groups => [:development, :test]