デプロイ時の修正

backend/Gemfile

@@ -35,6 +35,7 @@ gem "thruster", require: false
 # Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin Ajax possible
 gem "rack-cors"
 gem 'jwt'
+gem 'sprockets-rails'
 
 group :development, :test do
   # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem