Add a metadata column to user

[Thiteago]

Hey guys, I've been using seerr for a while now and it's amazing. It automated a manual process that I had been dealing with for a long time.

However, I think there's one thing missing in the user data.

I want to use webhook notifications to send external WhatsApp messages to users, but the current user data doesn't include that kind of information.

So I thought it would be really helpful to have a metadata/custom fields section for users.

With that, administrators could store custom information and include it in webhook payloads, making the system much more flexible for different use cases.

What do you guys think? If the idea makes sense, I can open a PR for this feature. I just want to make sure I'm not going too far with the suggestion.

[Thiteago]

So, i was hype with the idea, and i just opened a PR for that, you can check here: #3063