[Bug]: Filtering characters by image not working

[mmorenodev]

Project

API (api.potterdb.com)

Bug description

I tried to filter and get all the characters that have an image different than null but none of the predicates worked.

Expected Behavior

Get all characters with an image defined.

Steps to reproduce

Hit the characters endpoint, this is one of the filters I tried
https://api.potterdb.com/v1/characters?filter[image_not_null]

Screenshots

![DESCRIPTION](LINK.png)
N/A

Logs

N/A

[danielschuster-muc]

Thank you for opening this issue. The problem lies probably here. The same problem seems also to occur in other controllers (books, chapters, movies, potions, spells).