Support enumeration fields

[drenda]

I'm using Spring Boot, Spring Data Rest and this library.
I followed this tutorial https://www.baeldung.com/rest-api-search-language-rsql-fiql and everything works fine.

I've a problem when a field is an enumeration. In this query:

http://localhost:8082/api/v1/contacts/search?query=type==CUSTOMER

type field is an enumeration defines as:

```

@NotNull
@Enumerated(EnumType.STRING)
@column(nullable = false, columnDefinition = "VARCHAR(30) DEFAULT 'CUSTOMER'")
private ContactType type = ContactType.CUSTOMER;

how am I supposed to make the filter work?

Thanks

[odemura]

you could have added a stack trace.
we use tennaito/rsql-jpa and no problems with @Enumerated @Columns whatsoever,
and it does nothing special for them at all
https://github.com/tennaito/rsql-jpa/blob/master/src/main/java/com/github/tennaito/rsql/jpa/PredicateBuilder.java#L259
https://github.com/tennaito/rsql-jpa/blob/master/src/main/java/com/github/tennaito/rsql/jpa/PredicateBuilder.java#L390