@Entity
@Table(name = "users")
public class UsersModel implements Serializable{
	private static final long serialVersionUID = 1L;

	public UsersModel() {
		super();
	}

	@Id
	@GeneratedValue (strategy = GenerationType.AUTO)
	@Column(name="userId", unique=true, nullable=false)
	private Long userId;
...

- Class "org.customShop.users.UsersModel" is managed, but is not listed in the persistence.xml file

	<persistence-unit name="customShop" transaction-type="JTA">
	<provider>org.hibernate.ejb.HibernatePersistence</provider>
	<jta-data-source>java:/customShopDatasource</jta-data-source>
	<class>org.customShop.users.UsersModel</class>

The jar-file and class elements specify managed persistence
classes: entity classes, embeddable classes, and mapped superclasses. The jar-file element
specifies JAR files that are visible to the packaged persistence unit that contain managed
persistence classes, while the class element explicitly names managed persistence classes.