adding everything

backend/.gitattributes

backend/.gitignore

backend/Dockerfile

backend/build.gradle

backend/gradle/wrapper/gradle-wrapper.jar

backend/gradle/wrapper/gradle-wrapper.properties

backend/gradlew

backend/gradlew.bat

backend/settings.gradle

backend/src/main/java/kisbe32/backend/AuthController.java

...end/src/main/java/kisbe32/backend/BackendApplication.java

backend/src/main/java/kisbe32/backend/LoginRequest.java

...nd/src/main/java/kisbe32/backend/OrderItemRepository.java

backend/src/main/java/kisbe32/backend/OrderRepository.java

backend/src/main/java/kisbe32/backend/ProductRepository.java

backend/src/main/java/kisbe32/backend/User.java

backend/src/main/java/kisbe32/backend/UserRepository.java

backend/src/main/java/kisbe32/backend/WebConfig.java

backend/src/main/resources/application.properties

...end/src/test/java/kisbe32/backend/ApiIntegrationTest.java