add user model

sth-backend/src/main/java/hdm/mi/sthbackend/model/User.java

-package hdm.mi.sthbackend.model;import org.apache.logging.log4j.LogManager;
+package hdm.mi.sthbackend.model;
+
+import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import java.util.Map;
+import java.util.UUID;
+
 public class User {
     private final Logger log = LogManager.getLogger("User");
 
+    private UUID userId;
+    private String name;
+    private Map<UUID, Tournament> tournaments;
+
 }