code: @JsonIgnore
  	public Collection<? extends GrantedAuthority> getAuthorities() {
  		if (user.isAdmin()) {
  			return Collections.singleton(new SimpleGrantedAuthority(Roles.ADMIN.toString()));
  		} else if (user.isModerator()) {
  			return Collections.singleton(new SimpleGrantedAuthority(Roles.MOD.toString()));
  		} else {
  			return Collections.singleton(new SimpleGrantedAuthority(Roles.USER.toString()));
  		}
  	}
docs: A list of roles for this user.
  @return a list of roles