@ManyToMany(fetch = FetchType.EAGER, targetEntity = Role.class)
    @JoinTable(name = "user_role",
            joinColumns = {@JoinColumn(name = "user_id", foreignKey = @ForeignKey(name = "FK_USER_OF_ROLE"))},
            inverseJoinColumns = {@JoinColumn(name = "role_id", foreignKey = @ForeignKey(name = "FK_ROLE_OF_USER"))})
    private Set<Role> roles;