initial commit for backend server basic

.gitignore

.mvn/wrapper/maven-wrapper.jar

.mvn/wrapper/maven-wrapper.properties

mvnw

mvnw.cmd

pom.xml

...ple/accessingdatamysql/AccessingDataMysqlApplication.java

...n/java/com/example/accessingdatamysql/MainController.java

src/main/java/com/example/accessingdatamysql/User.java

...n/java/com/example/accessingdatamysql/UserRepository.java

src/main/resources/application.properties

...ccessingdatamysql/AccessingDataMysqlApplicationTests.java