Add missing Table import to User entity

Author: Alexander-Rees

backend/src/main/java/com/example/demo/model/User.java

@@ -4,6 +4,7 @@
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
+import jakarta.persistence.Table;
 
 @Entity
 @Table(name = "user")